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Random Miss/Stutter

RumPunch

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Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
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.


 


Uncle Gump

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My credo
Lead, Follow or get out of my way
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

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Location
Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
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

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Location
Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
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.
IMG_20220612_124323911.jpg
IMG_20220612_124339314.jpg
 

RumPunch

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Messages
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Location
Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
Also changed ECM out of an 88 Auto truck and issue stayed the same.
 

RumPunch

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Location
Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
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

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Messages
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Location
Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15
Changed regulator back to original as well, same.
 

RumPunch

Well-Known Member
Supporting Member
Law Enforcement
Joined
Jan 12, 2021
Messages
711
Reaction score
669
Points
93
Location
Walkerton Va 23177
Vehicle Year
1988
Make / Model
Ford Bronco II
Engine Type
2.9 V6
Transmission
Automatic
2WD / 4WD
4WD
Total Lift
3"
Tire Size
31x10.50R15

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