COP question need help

[Ralph50]

The truck used to miss across the RPM range.

Now its ok at the lower end but flutters under WOT.

CEL/SES light comes and goes but no trouble codes on the Predator???

The reason this is sooo annoying is that it will work fine one minute and miss the next. SMH

Do you guys think it could be a bad COP???

How can i figure out which one it is considering the miss comes and goes???

 

[SID297]

Has the truck sat for a long period of time? Have you changed the fuel filter? I had a similar issue that ended up being a fuel related issue.

 

[rich5150]

The truck used to miss across the RPM range.

Now its ok at the lower end but flutters under WOT.

CEL/SES light comes and goes but no trouble codes on the Predator???

The reason this is sooo annoying is that it will work fine one minute and miss the next. SMH

Do you guys think it could be a bad COP???

How can i figure out which one it is considering the miss comes and goes???

If the CEL light flashes.... as you are under heavy load, that's the computer telling you it detects knock and is actively pulling timing. Stay out of it. Try SID's suggestion, replace the fuel completley with good 93 octane, even a bottle of "dry-gas" might not be a bad idea to disapate any water that may be present.

 

[Ralph50]

Thanks,

Fuel filter is new <10,000 miles.

The truck was definitely missing at low rpms and idle.

I was assuming it was either a stuck injector or a bad COP.

I was going to start pulling the connectors on the injectors and COPs to isolate the cylinder as a bad COP would have a different OHM reading once tested.

Since the problem comes and goes I don't know what cylinder is misfiring.

The Predator does not read any errors even with the CEL on?

I just wish whatever it is would just break so I could isolate the problem.

 

[Canadian_Bacon]

10K is not new to a fuel filter. Replace it.

 

[rich5150]

Thanks,

Fuel filter is new <10,000 miles.

The truck was definitely missing at low rpms and idle.

I was assuming it was either a stuck injector or a bad COP.

I was going to start pulling the connectors on the injectors and COPs to isolate the cylinder as a bad COP would have a different OHM reading once tested.

Since the problem comes and goes I don't know what cylinder is misfiring.

The Predator does not read any errors even with the CEL on?

I just wish whatever it is would just break so I could isolate the problem.

Measuring resistance across the COP's isn't going to tell you much next to the fact that one may be 100% shot....as in non-functional. The only way to properly test an ignition system is under normal operation/load.

I've had a plethora of modulars in the last 10 years of my life.. I've not had a single bad COP go bad yet, other than physically cracking due to heat and obvious replacement. Try checking your fuel & a new set of plugs.

 

[hotcobra03]

ive had issues on my cobra with cop`s...car spit and spuddered while trying to stay steady or accelerate...

i had found a member close bye to try a good set of coils...


guess mine were weak...new coils fixed the issue...


goodluck finding cheap coils...ford racing sells a set but for 4v...

if you got guts...ebay has 8 motorcraft fine wire plugs with 8 china coils for 99 bucks

 

[Ralph50]

I guess I just have to wait and see.

The plugs have least than 5k on them.

Last time they were misfiring the codes told me exactlly which cylinder it was.

This time no codes.

Thanks for the advice.

 

[lightningmanny]

check your gap....and reload your tune

 

[FireGuy]

check your gap....and reload your tune

This ^^^ plus a new set of plugs. They are cheap and can fail. I have seen a new set of TR6's miss randomly. Followed with another set, smooth a silk. Just another opinion of course.

 

[gr850]

Haven't had the problem on my L but I had an issue with my P71 Crown Vic, same CoP's as on the L 5.4.

I had a CoP that was fine when first started etc. After a short time the CoP would warm up and start to miss, especially under load. I checked the ohm's and no problem(1.0 +/-.2 cold) if I recall correctly. It was only after I gloved up and checked the ohm's when the CoP's were hot that I realized a Cop was breaking down and missing. The ohms were really off the scale. I replaced it and good to. However a couple others quickly followed so I replaced all of them.

Amazon sells Accell CoP's very cheap. Not as good as OEM but the price is right.

 

[SID297]

If there's even a possibility that you have a cruded up fuel system buy this and pour it in your tank:

Buy Chevron Techron Concentrate Fuel System Cleaner (20 oz.) 65740 at Advance Auto Parts

I've had really good luck with it. I'm going to be writing an article on it soon.

 

[Ralph50]

Guess what???

Drove the truck around yesterday and all is well. SMH

I still don't know what it is.