light miss stumble low load low rpm

[genesmob]

Hi guys
,
I have an annoying miss stumble on my 2007. It has a TVS JLT 127 FRPP monoblade LTs etc. Ive been working on it with my tuner but haven't had any luck. I think its something mechanical because it idles perfect and everything else is perfect. Ive sprayed every connection and the blower base down with brake clean and no fluctuation in idle. New front 02 sensors, Maf sensor, new fuel filter and plugs. Moved filter back and forth on the JLT. The motor idles perfect and responds instantly. Top end AF is perfect as are all other manners of car. The stumble is there when cruising steady throttle at hi vacuum (low load) and disappears when I go up hill (more load) or give it gas.
When it does this, my wideband fluctuates wildly from 14.2 to 15.8 . wideband is perfectly smooth at idle and up to 1300 rpm in gear. It also stumbles in neutral when I rev it above 1400 rpm. Ive also gotten code P0300 once or twice. I thought someone here might have experienced this and found a solution. Any help would be greatly appreciated.

Thanks

 

[ShelbyGT5HUN]

I had a similar problem in a different V8 set up than you, a stumble under light load or cruise. Runs great in any other condition. If I just gave it enough throttle to 1200-1400rpms, at idle and parked in neutral, I could get the stumbling to occur 100% of the time, for as long as I held the throttle a CRACK off idle. Idle speed on this car was 850rpms with the throttle plate closed. It felt like a bad spark plug.....

Turned out it was the EGR system. The EGR valve was sticky, and would bleed hot exhaust gas, when it shouldn't, causing the stumble. Car would idle, totally fine, not a miss. Under anything except light cruise, the car ran, drove, and made great power. Drove me nuts for two years. I tried everything! I sold the car, and the new owner, noticed it, and I said I had no clue, maybe a worn out TPS. He dove into it, and found the problem was with the EGR!

Your code, and the lean condition you are describing sounds just like my problem.

 

[genesmob]

I was thinking about the egr. Thanks

 

[fullboogie]

I had a similar problem in a different V8 set up than you, a stumble under light load or cruise. Runs great in any other condition. If I just gave it enough throttle to 1200-1400rpms, at idle and parked in neutral, I could get the stumbling to occur 100% of the time, for as long as I held the throttle a CRACK off idle. Idle speed on this car was 850rpms with the throttle plate closed. It felt like a bad spark plug.....

Turned out it was the EGR system. The EGR valve was sticky, and would bleed hot exhaust gas, when it shouldn't, causing the stumble. Car would idle, totally fine, not a miss. Under anything except light cruise, the car ran, drove, and made great power. Drove me nuts for two years. I tried everything! I sold the car, and the new owner, noticed it, and I said I had no clue, maybe a worn out TPS. He dove into it, and found the problem was with the EGR!

Your code, and the lean condition you are describing sounds just like my problem.

Been experiencing this too - what's the fix? New EGR valve, or EGR solenoid?

 

[genesmob]

From what Ive read, its the sip (dpfe) sensor which is attatched to the egr valve. I ordered a new egr valve assembly motorcraft part cx2096 that includes the sensor. I should have it Thursday. I will post the results good or bad.

 

[fullboogie]

Please do. I'd love to fix this irritating behavior.

 

[nxhappy]

- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure

Check the COPs. Ford is known for this.

 

[genesmob]

- Faulty spark plug (s)
- Faulty ignition coil (s)
- Clogged or faulty fuel injector (s)
- Intake air leak
- Fuel injectors harness is open or shorted
- Fuel Injectors circuit poor electrical connection
- Ignition coils harness is open or shorted
- Ignition coils circuit poor electrical connection
- Insufficient cylinders compression
- Incorrect fuel pressure

Check the COPs. Ford is known for this.[/QUOTE

Thanks. Did your car have the same problem and the fix was new coils? My car does not miss under load Just low load steady state conditions.

 

[fullboogie]

I don't know why you always post that Ford is "known" for "bad" COPs. In my 12 years of owning mod motors, you are the only person who has ever said that. In fact, all I've ever heard is that factory coils are the absolute best option and most reliable. What do you base your opinion on?

 

[genesmob]

Have to add this. If I start the car, and I hold rpm above 1400 right away, the A/F is steady and it doesnt stumble until about 10 to 15 seconds into it then the A/F starts bouncing. Maybe that's just post start enrichment (just thinking out loud). Fullboogie, I agree, coil on plug is the shit!!

 

[54First]

-
Check the COPs. Ford is known for this.

I don't know why you always post that Ford is "known" for "bad" COPs. In my 12 years of owning mod motors, you are the only person who has ever said that. In fact, all I've ever heard is that factory coils are the absolute best option and most reliable. What do you base your opinion on?

"Known for that" is one of his favorite lines. Not just Ford. Other parts, too.

Steve

 

[nxhappy]

I don't know why you always post that Ford is "known" for "bad" COPs. In my 12 years of owning mod motors, you are the only person who has ever said that. In fact, all I've ever heard is that factory coils are the absolute best option and most reliable. What do you base your opinion on?

13 years working on Fords.

Plus, the OPs code points to faulty ignition coil.

are you going to bitch, or actually contribute to fixing the issue ?

 

[ShelbyGT5HUN]

Im betting on the EGR.

 

[ShelbyGT5HUN]

Been experiencing this too - what's the fix? New EGR valve, or EGR solenoid?

This was a non-Ford V8, but it took a new EGR valve.

 

[VNMOUS1]

I don't know why you always post that Ford is "known" for "bad" COPs. In my 12 years of owning mod motors, you are the only person who has ever said that. In fact, all I've ever heard is that factory coils are the absolute best option and most reliable. What do you base your opinion on?

They're not known for bad cop at all.

 

[fullboogie]

are you going to bitch, or actually contribute to fixing the issue ?

Bitch? There's no bitching going on here kid. You jump into every post you can and say either: (1) "It's the COPS - they're known for going bad"; or (2) "It's the cats - they're known for going bad."

Seems that you are the one not contributing anything worthwhile.

 

[1320 Junkie]

I've never seen a Mod motor coil take a shit on a ford in 17 years of owning mod motored Cobras. Now BMW's and Audi's....yeah those ****ers COP units suck and go bad all the time!

EGR is my guess also or spark plug related OP. What heat range plug and gap are you running?

 

[genesmob]

Im running new tr 6s gapped at .028. No miss at 19psi

 

[1320 Junkie]

That gap is fine...I would look into the SIP sensor as stated before and also clean your maf sensor. Also position your filter at the end of your cold air tube as far as you can go. Good luck.

 

[genesmob]

Ive moved the filter out and in as far as possible with no change and I cleaned the maf sensor. Just waiting for the new egr valve to get here so I can try it. Thanks