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surging problem

Posted: 2021 Mar 30, 17:39
by GoldCO
hey folks, someone over at FTE forum suggested you guys might be able to answer my question…

running a 5.8 in my '52 F3 — donor motor (rebuilt), harness, PCM came from a '95 F150. the original PCM had the "leaky capacitor" issue, but I was able to find another from a local junkyard. truck ran perfectly fine for 18 months or so, then started "bucking" — let off the throttle and RPMs would surge 3x before settling. also had a couple of instances where it seemed the TC would remain locked up when I came to a stop. :o

just ordered a remanufactured PCM from "autozone": BSE Remanufactured Engine Control Computer ECC2517 (OEM #F5TF-YB). installed it, and thought it had solved the problem on the initial test drive, but then the next day the surging returned, though not as severe. popped the PCM open, and you can see where there they replaced that same capacitor (IC pretty scratched up).

my question is: any chance this reman unit may be bad, or, should I be looking at something else causing this issue? as mentioned, truck ran flawlessly the first year and half.

thanks for any insight. 8-)

Re: surging problem

Posted: 2021 Mar 30, 19:11
by decipha
sounds like a bad idle air control valve

Re: surging problem

Posted: 2021 Mar 30, 19:55
by GoldCO
decipha wrote: 2021 Mar 30, 19:11 sounds like a bad idle air control valve
hmmm... hadn't thought of that. thanks for the tip!

Re: surging problem

Posted: 2021 Apr 13, 19:56
by GoldCO
Thank you, decipha

Replaced the IAC valve and (knock on wood) no more surging.
Much appreciated!
8-)

Re: surging problem

Posted: 2021 Apr 21, 13:50
by decipha
yeah np