1997 mustang cobra problem please help

Mpoitrast87

Mpoitrast87

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My 03 cobra did the same thing. Would idle great then out of nowhere it would run on what seemed like 4 cylinders and could hardly drive it. Then it would clear up on its own and would run great again. Never figured it out.
 
Makobra

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xblitzkriegx said:
funny you would say that. i have the oem coils and WIRES on my 97 and it runs perfect.
Click to expand...

great. your wires are not suspect. his are.

anything having to do with ignition is suspect right now
anything having to do with fuel is suspect right now.

even new parts just installed on the car.
cars don't behave randomly, they only seem that way when we don't know what we are looking at.

this doesn't make sense and if something doesn't make sense one of your assumptions are wrong. at least.
 
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Phillip Scocca

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Sorry I haven’t been on in a while had family problem,

I just let the car warm up and drove it around it’s throwing another code P0351 and code P0308
 
Makobra

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your problem could be anything from your ECM to the spark plug.
trace every wire, the coil, the plug wires, everything, and you will find your problem.

if you swap everything from a good cylinder to the bad cylinder and its still the cylinder your problem is probably either your harness or your ECM itself.

its one of these things (as noted by the code)
  • Faulty Ignition Coil 1
  • Ignition Coil 1 harness is open or shorted
  • Ignition Coil 1 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)
 
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Phillip Scocca

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Makobra said:
your problem could be anything from your ECM to the spark plug.
trace every wire, the coil, the plug wires, everything, and you will find your problem.

if you swap everything from a good cylinder to the bad cylinder and its still the cylinder your problem is probably either your harness or your ECM itself.

its one of these things (as noted by the code)
  • Faulty Ignition Coil 1
  • Ignition Coil 1 harness is open or shorted
  • Ignition Coil 1 circuit poor electrical connection
  • Faulty Engine Control Module (ECM)
Click to expand...


Yeah I swapped everything still the same, I have a new ecm coming in tomorrow, I’m also going to go over the wires again, thank you for you’re help
 
Makobra

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I would test every single one of the wires going to that coil pack to see if they are shorting out somewhere if the ECM doesn't fix it. weird stuff is exactly what a bad ecm looks like so hopefully that does the trick.
 
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Phillip Scocca

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Makobra said:
I would test every single one of the wires going to that coil pack to see if they are shorting out somewhere if the ECM doesn't fix it. weird stuff is exactly what a bad ecm looks like so hopefully that does the trick.
Click to expand...

Looks like each coil pack has 3 wires to each I tested it with a test light and only the center wires lite it up on each connector to the coil
 
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if the ecm doesn't fix your problem test for connectivity all the way from the coil pack connector to the pin where they come out at the harness connector on the passenger side where the engine harness plugs into the main one. then if that is good test from that harness all the way to the ECM pins.

just use a multimeter and set it to ohms, some of them have a audible beep when it completes the circuit. you're looking for a broken circuit. three wires shouldn't be that bad to hunt down.
 
hotcobra03

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Trouble Code:p0308 (4.6L V8 VIN X Std)
Cylinder Number 8 Misfire Detected
Print this code data
print.png

Number of Trips to Set Code: 2

  • MISFIRE Details
  • MIL Details
Trouble Code Conditions:
DTC P0136, P0156, P0171, P0172, P0175, P1130 and P1150 not set, engine started, engine running under positive torque conditions, and the PCM detected a misfire a misfire in Cylinder 8 during the 200 revolution (Catalyst) or 1000 revolution (High Emissions) period. Note: If the misfire is severe, the MIL will flash on/off on the 1st trip!

Possible Causes:

  • Air leak in the intake manifold, or in the EGR or PCM system

  • Base engine mechanical problem that affects only Cylinder 8

  • Fuel delivery component problem that affects only Cylinder 8 (i.e., a contaminated, dirty or sticking fuel injector)

  • Ignition system problem (coil, plug) that affects only Cylinder 8

  • TSB 02-16-2 contains repair help for this code (LS & T-Bird)

  • TSB 03-14-4 contains repair help for this code for COP ignition
 
hotcobra03

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Listen
HD: Misfire Detection Monitor

1997 PCED On Board Diagnostics II A


SECTION 5A: Pinpoint Tests


HD: Misfire Detection Monitor

← HD: Introduction
HD1 CHECK POSSIBLE CAUSES OF MISFIRE


NOTE
Note: Running out of fuel can turn on the MIL and possibly store a Continuous Misfire DTC.



Misfire Continuous Memory Diagnostic Trouble Codes (DTCs):

  • P0301 - Cyl No.1, Fuel Inj. Test Pin 75

  • P0302 - Cyl No.2, Fuel Inj. Test Pin 101

  • P0303 - Cyl No.3, Fuel Inj. Test Pin 74

  • P0304 - Cyl No.4, Fuel Inj. Test Pin 100

  • P0305 - Cyl No.5, Fuel Inj. Test Pin 73

  • P0306 - Cyl No.6, Fuel Inj. Test Pin 99

  • P0307 - Cyl No.7, Fuel Inj. Test Pin 72

  • P0308 - Cyl No.8, Fuel Inj. Test Pin 98

  • P0309 - Cyl No.9, Fuel Inj. Test Pin 68

  • P0310 - Cyl No.10, Fuel Inj. Test Pin 42
Possible causes:

  • Ignition System.

  • Fuel Injectors.

  • Fuel Pressure.

  • Evaporative Emission System.

  • EVAP Canister Purge Valve.

  • Base Engine.

  • Running out of fuel.
Has the vehicle recently run out of fuel?


Yes No
OBD II system OK. COMPLETE PCM Reset to clear DTCs. RETURN vehicle to customer. GO to HD2.
HD2 CHECK DAMPER AND PULLEY ASSEMBLY

  • All others:CAUTION: Remove the front cover if necessary to observe the crank pulley.
  • Key off.

  • Observe the crank pulley for wobble.

  • Examine the EI pulse ring fastened to the harmonic fastener.
Does the crank pulley wobble or is the pulse ring loose or damaged?


Yes No
REPLACE the pulley or damper assembly. RERUN Quick Test. GO to HD3.
HD3 CHECK FOR OTHER NON-MISFIRE CONTINUOUS MEMORY DTCS


NOTE
Note: Check for other non-misfire Continuous Memory DTCs which could cause the misfire DTC.



Possible causes:

  • Camshaft Position (CMP) Sensor.

  • Octane Adjust (OCT ADJ).

  • Ignition Coil Primary Circuit.

  • Knock Sensor (KS).
Are other non-misfire Continuous Memory DTCs present?


Yes No
ADDRESS the next Continuous Memory DTC. DISREGARD Misfire DTC at this time. Go to Section 4A for Powertrain DTC Charts. GO to HD4.
HD4 CHECK FOR ON-DEMAND SELF-TEST DTCS


NOTE
Note: Check for any key on, engine off DTCs which could cause the Misfire DTC.



Are any key on, engine off DTCs displayed on the Scan Tool?


Yes No
Go to Section 4A, Powertrain DTC Charts, and PROCEED as required.
Coil On Plug applications:

GO to Pinpoint Test Step JF1.

All others:

GO to JB1 to evaluate spark plugs and secondary wires. If OK, GO to HD5.
HD5 CHECK FOR OTHER KEY ON ENGINE RUNNING DTCS


NOTE
Note: Check for any other key on, engine running DTCs which can cause the Misfire DTC.



Are any additional key on, engine running DTCs displayed on the Scan Tool?


Yes No
If DTCs P1131, P1137, P1151 or P1157 are present, GO to HD8.

All others: Go to Section 4A, Powertrain DTC Charts, and PROCEED as required.
Vehicles with D.P.F. EGR Systems: GO to HD6.

All others: GO to HD8.
HD6 CHECK/COMPARE PID VALUES
  • Key off.

  • Connect Scan Tool.

  • Accessories off (A/C, heater, etc.).

  • Start engine and warm to normal operating temperature.

  • Access DPFEGR PID with the Scan Tool.

  • Key on, engine off.

  • Record DPFEGR PID value.

  • Start engine, let idle.

  • Compare key on, engine off and engine running PID values.
Was engine running PID value within 0.15 volt of key on, engine off value?


Yes No
Disconnect Scan Tool. GO to HD8. GO to Pinpoint Test Step HE100.
HD8 CHECK RESISTANCE OF FUEL INJECTOR(S) AND HARNESS
  • Key off.

  • Disconnect PCM. Inspect for damaged or pushed out pins, corrosion and loose wires. Service as necessary.

  • Install breakout box, leave PCM disconnected.

  • Measure resistance between suspect fuel injector test pin and Test Pin 71 or 97 at the breakout box. Refer to the list in HD1.
Is the resistance between 11.0-18.0 ohms?


Yes No
Fuel injector and harness resistance is OK. GO to HD9. GO to Pinpoint Test Step H56 to diagnose fuel injectors.
HD9 CHECK INJECTOR DRIVER SIGNAL
  • Key off.

  • Breakout box installed.

  • Connect PCM to breakout box.

  • Connect Test Lamp between Test Pin 71 or 97 and suspect injector test pin.

  • Start engine.
Does test lamp have a dim glow while running engine?


Yes No
GO to HD10. No light or bright light: REPLACE PCM. REMOVE breakout box. RERUN Quick Test.
HD10 CHECK FUEL PRESSURE

  • WARNING: THE FUEL SYSTEM WILL REMAIN PRESSURIZED WHEN ENGINE IS NOT RUNNING. TO PREVENT INJURY OR FIRE, USE CAUTION WHILE WORKING ON THE FUEL SYSTEM.
  • Key off.

  • Install fuel pressure gauge.

  • Start and run engine at idle. Record fuel pressure.

  • Increase engine speed to 2500 rpm and maintain for one minute. Note and compare fuel pressure.
Is fuel pressure between 210-310 kPa (30-45 psi)?


Yes No
GO to HD11. GO to Powertrain/Fuel System Group in the Service Manual.
HD11 CHECK ABILITY OF FUEL SYSTEM TO HOLD FUEL PRESSURE
  • Start and run engine at idle. Note fuel pressure.

  • Increase engine speed to 2500 rpm and maintain for one minute.

  • Look for fuel leaking at the fuel injector O-ring, fuel pressure regulator and the fuel lines to the fuel charging assembly. Service as necessary.

  • Turn engine off.

  • Key on, engine off.
Does fuel pressure remain at specification within 16.5 kPa (5 psi) for 60 seconds?


Yes No
GO to HD12. GO to Powertrain/Engine or Fuel System Group in the Service Manual to determine which area within the Fuel Delivery System is at fault.
HD12 CHECK FUEL INJECTOR FOR FLOW AND LEAKAGE
  • Refer to Warning, Caution and Handling at the beginning of Pinpoint Test HC to avoid fuel spillage and injury.

  • Verify that the flow rate for each fuel injector is within specification using Injector Flow Tester.
Is flow rate for each fuel injector within specification?


Yes No
Fuel delivery system is not likely to have caused the Misfire DTC. GO to HD20 to diagnose the vacuum system. REPLACE or CLEAN the inoperative fuel injector(s) as required. RERUN Quick Test.
HD20 CHECK VACUUM SYSTEM
  • Inspect all vacuum lines for damage, such as pinched lines, cracks, proper routing and assembly.

  • Refer to the Electrical and Vacuum Troubleshooting Manual (EVTM) for vacuum service information and repair.
Is the vehicle vacuum system OK?


Yes No
GO to HD21. SERVICE the vacuum system. REFER to the Electrical and Vacuum Troubleshooting Manual. RERUN Quick Test.
HD21 CHECK EVAPORATIVE EMISSION SYSTEM

  • The Misfire Monitor can be influenced by Evaporative Emission System. The next four Pinpoint Test steps will diagnose the Evaporative Emission System.
  • Check the fuel vapor storage canister for fuel saturation.
Is there an excess amount of liquid fuel present in the fuel vapor storage canister?


Yes No
REPLACE fuel vapor storage canister. RERUN Quick Test. GO to HD22. CHECK fuel tank vent system.
HD22 PRESSURE TEST EVAPORATIVE EMISSION SYSTEM
  • Key OFF.

  • Install Rotunda Evaporative Emission System Tester 134-00056 or equivalent at the EVAP SERVICE port, if equipped, or the fuel filler cap.

  • Follow test instructions from the Tester Kit.
Is evaporative emission system holding pressure?


Yes No
GO to HD23. SERVICE as necessary. RERUN Quick Test.
HD23 CHECK VACUUM IN EVAPORATIVE EMISSION SYSTEM
  • Check for blockage/restrictions or cut hoses between engine vacuum port and fuel vapor storage canister.

  • Check for blockage in fuel tank vent system.
Is there a fault indicated?


Yes No
REPLACE damaged vacuum hoses, or REMOVE blockage/restrictions. RERUN Quick Test.
For vehicles with EVAP Canister Purge valve:

GO to HD24.

For vehicles with VMV:

GO to HD26.
HD24 CHECK EVAP CANISTER PURGE VALVE

  • This pinpoint test step will verify the mechanical integrity of EVAP Canister Purge valve. The valve and circuit have been checked electrically and reported during KOEO Self-Test.
  • Key off.

  • Disconnect EVAP Canister Purge valve.

  • CAUTION: Observe proper pin orientation.

  • Connect 12 volt DC power source to valve.

  • Connect positive power source to VPWR circuit and negative lead to EVAP Canister Purge circuit at the EVAP Canister Purge valve harness connector.

  • Apply 53 kPa (16 in-Hg) of vacuum to the manifold side of the EVAP Canister Purge valve. Apply power source.
Does the valve open and pass air freely?


Yes No
Evaporative Emission system is functioning properly. GO to HD25for Base Engine concerns. REPLACE EVAP Canister Purge valve. RERUN Quick Test.
HD25 CHECK FOR BASE ENGINE CONCERNS

  • This Pinpoint Test step will determine if there are any base engine concerns that may have caused the Misfire DTC or drive concern.Perform the following tests in order to evaluate base engine integrity:
  • Perform an Engine Compression test.

  • Perform Dynamic Valve Train analysis.

  • Check Positive Crankcase Ventilation System.

  • Check possible leakage points.

  • Refer to the Diagnosis and Testing procedures in the Powertrain/Engine Group of the Service Manual for all of the above procedures.
Is any service required?


Yes No
GO to Powertrain/Engine Group in the Service Manual, Diagnosis and Testing, to make repairs. RERUN Quick Test. The cause of the Misfire DTC is intermittent. To diagnose the Ignition System, GO to the Intermittent Ignition procedure in Pinpoint Test Step Z50. FOLLOW Instructions for using the Rotunda Electronic Ignition System, also known as the Distributor/less Ignition System Tester (DIST) tool.
HD26 CHECK FOR VMV HOUSING LEAKS
  • Key off.

  • VMV electrially connected.

  • Install a hand vacuum pump to the fuel vapor port to fuel vapor storage canister on the VMV vacuum at line.

  • Apply 53 kPa (16 in-Hg) of vacuum with the vacuum pump.
Does the VMV hold vacuum at room temperature?


Yes No
GO to HD27. REMOVE vacuum pump. REPLACE damaged VMV. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test.
HD27 CHECK FOR FILTER CONTAMINATION OR DAMAGE ON VMV
  • Key off.

  • Vacuum line from input vacuum port to intake manifold on the VMV (control vacuum solenoid part of valve) is removed.

  • Install a hand held vacuum pump to the open input vacuum port on the VMV.

  • Apply 48-52 kPa (10-15 in-Hg) of vacuum to the VMV.
Does the VMV hold vacuum or is the valve very slow to release vacuum to atmosphere?


Yes No
SERVICE VMV filter. If unable to clean filter or REMOVE blockage to filter, REPLACE VMV. RECONNECT all components. COMPLETE PCM Reset to clear DTCs. RERUN Quick Test. REMOVE vacuum pump. RECONNECT all components. GO to HD25.
HD30 CHECK FOR ADDITIONAL MISFIRE DTCS
Diagnostic Trouble Code P0300 indicates multiple cylinders are misfiring or PCM cannot identify which cylinder is misfiring.

Possible causes:

  • Camshaft Position Sensor (CMP)

  • Low fuel: less than 1/8 tank

  • Stuck open EGR valve
Are any other misfire DTCs present?


Yes No
GO to HD1. GO to HD31.
HD31 CHECK FOR OTHER CONTINUOUS MEMORY DTCS
Are other Continuous Memory DTCs present?


Yes No
Go to Section 4A for Powertrain DTC Charts. PROCEED as required. GO to HD32.
HD32 CHECK/COMPARE PID VALUES
  • Key off.

  • Connect Scan Tool.

  • Accessories off (A/C, heater, radio, etc.).

  • Start engine and warm to normal operating temperature.

  • Access DPFEGR PID with the Scan Tool.

  • Key on, engine off.

  • Record PID value.

  • Start engine, let idle.

  • Compare key on, engine off and engine running PID values.
Was engine running DPFEGR PID value within 0.15 volt of key on, engine off value?


Yes No
DISCONNECT Scan Tool. GO to HD8. GO to Pinpoint Test Step HE100.
HD40 CHECK CMP SENSOR OUTPUT

  • Diagnostic Trouble Code (DTC) P1309 indicates Misfire Detection Monitor is not enabled.
  • Key off.

  • Breakout box installed, PCM disconnected.

  • Connect digital multimeter between Test Pin 85 (CMP) and Test Pins 51 or 103 (PWR GND) at the breakout box.

  • Bump engine in short burst with the starter without starting engine for at least 10 engine revolutions.
Does digital multimeter reading switch between low (less than 2.0 volts DC) and high (greater than 8.0 volts DC)?


Yes No
REPLACE CMP sensor. REMOVE breakout box. RECONNECT all components. RERUN Quick Test.
  • Intro
 
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Phillip Scocca

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Makobra said:
if the ecm doesn't fix your problem test for connectivity all the way from the coil pack connector to the pin where they come out at the harness connector on the passenger side where the engine harness plugs into the main one. then if that is good test from that harness all the way to the ECM pins.

just use a multimeter and set it to ohms, some of them have a audible beep when it completes the circuit. you're looking for a broken circuit. three wires shouldn't be that bad to hunt down.
Click to expand...


Well I put a new ECM in the car and it threw all transmission codes P0705, P0755, P0708, P0743 and the car ran way worse was stalling I check wires I’ll check again
 

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