Random Miss/Stutter

[RumPunch]

Really running out of thoughts here. Injectors changed(not ruling out sending them in to get tested) temp sensors all swapped and working, MAP new(since rebuild) timing quadruple checked, plugs changed again, sprayed 3 cans of brake clean around engine no leaks found, fuel pressure good... I'm sure I missed something. New O2. Runs terrible when cold, the hotter it gets, the better. IE like 20-30 minutes of runtime under load at 90+ degrees it almost goes away. Sits 20 minutes right back to acting up. Still only under low load.

New video · Saturday, Jun 4, 2022 🎬

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[Uncle Gump]

Looked like it held a nice steady idle... even sounded pretty good on a free rev. You may never get rid of the off idle stumble when you stab the throttle. But it sure looks as if she misses under light acceleration.

Ford engines always seemed to be sensitive to plug wire routing. Ford says if a plug wire crosses another... it should be at a 90 degree angle. So look at your wires... if you have a couple wires that are laying together... maybe try some cheap wire separators and get them separated and to cross each other at 90 degree angle or at least closer to 90 degree.

To me... what I saw in the video looked more ignition related... random. An injector... be it rich or lean is pretty consistent and doesn't come and go.

The next question... did you replace cap rotor and wires with the cheapest on Amazon? Maybe you still have the old motorcraft cap and rotor you can swap in to try.

 

[RumPunch]

Everything replacement was Motorcraft… I have questioned spark plug wire routing and honestly want to measure out and by a custom set to clean it up. Very good point that I meant to address and seemingly forgot in the process. Let me play around with that. Thanks

 

[RumPunch]

Well new custom MSD 8mm plug wires no change to the issue at all. Cold(first 10 minutes of run time) engine will nearly stall under light load, idle seems 95% fine. High load will, WOT seems ok once over 2k rpm. I need help… no codes. Once hot 10-20 minutes + issue diminishes 50% at least. Cools down, same issue.

 

[RumPunch]

Also changed ECM out of an 88 Auto truck and issue stayed the same.

 

[RumPunch]

32-33 psi fuel at idle and raises to approx 40 in higher rpm. I know spec is 35? Could this cause it? I just don’t see how.

 

[RumPunch]

Changed regulator back to original as well, same.

 

[RumPunch]

Believe it was the new TFI module I replaced

New video · Tuesday, Jul 26, 2022 🎬

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[GingerKing13]

Believe it was the new TFI module I replaced

New video · Tuesday, Jul 26, 2022 🎬

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What did you re-replace it with?

Is there a Motorcraft Part Number? Rockauto does not carry it.

 

[rusty ol ranger]

What did you re-replace it with?

Is there a Motorcraft Part Number? Rockauto does not carry it.

Just google "ford 2.9 motorcraft ignition module" you have a few options.

 

[RumPunch]

What did you re-replace it with?

Is there a Motorcraft Part Number? Rockauto does not carry it.

Here you are sir, still shows on Rockauto for me