P1351 one time before MPFI conversion, worse after (MISFIRE CYL 4)

[bigfootchiro]

East302, you are a wealth of knowledge, thank you! I have not swapped out the VCM yet, so would a relearn still need to be done? Wouldn't hurt to try anyway! I got told today that my trans may be on its way out and contributing to the issue. I'm taking it in for a second opinion on Monday, because the guy I bought it from said it has about 40K on it since it was built. Oil is still bright red and clean.

 

[willxfs]

Good luck bigfoot. Hope it's not the transmission. That aint cheap. Pull the distributor, it's really easy as long as you mark the base of the distributor in relation to a point on aluminium intake and the cap/pointer in two spots on the distributor side (as described in an earlier post).

 

[east302]

I have not swapped out the VCM yet, so would a relearn still need to be done?.

Oh, sorry, thought you had swapped it out earlier. I saw where you said you swapped the ignition control module and misread it as VCM.

No, I wouldn't worry about it then.



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[bigfootchiro]

Good luck bigfoot. Hope it's not the transmission. That aint cheap. Pull the distributor, it's really easy as long as you mark the base of the distributor in relation to a point on aluminium intake and the cap/pointer in two spots on the distributor side (as described in an earlier post).

Thank you, I will definitely give it a shot! It looks like I've been chasing 2 different gremlins. One looks like slightly low fuel pressure (49-51 PSI at idle), so it has a misfire at idle. If the pressure is bumped up to 60 PSI with a makeshift pump, all misfires go to 0. Supposedly the pump is going bad and is only a year old.

Today I found that the flex plate doesn't always turn with the TC, as if the TC bolts may be loose, which could be causing that clunk/jerk once TC is locked up.

It's crazy how you can think one thing is going on, then turns out to be something completely different. Wouldn't be fun if it were easy haha.

 

[bigfootchiro]

Oh, sorry, thought you had swapped it out earlier. I saw where you said you swapped the ignition control module and misread it as VCM.

No, I wouldn't worry about it then.



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Once all these gremlins leave, the next step is swapping out the dreaded black box for an 0411. Should work well with the MPFI!