PCM Going out?

skbishop90

Member
Apr 20, 2020
5
1
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Birmingham, AL
Hey guys (gals). New member here but long time Mustang owner.

I have a 2000 GT with the stock 4.6 2v. I have a list of mods but I recently installed Modular Head Shop stage two cams. I have a SCT tuner with online Bama tunes. I have to say, Im not very pleased with their tuning abilities BUT....I have issued that make me think its either their tunes or my PCM going on the fritz.

My question is, are there "new" PCMs for 99-04 cars? Or can I send mine in somewhere to be tested/refurbished?
 
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wmburns

SN Certified Technician
Aug 14, 2009
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My question is, are there "new" PCMs for 99-04 cars?
No. Any replacement PCM would be a re-man'ed unit.

or my PCM going on the fritz
Just wondering. Has the tune been loaded via a "plug in" chip? I would be concerned if this is a chip tune.

Does the car drive mostly OK? How about before the modifications were done? If so I don't think it's likely that the PCM is "going out". It seems more likely that the PCM is getting bad data. Or at the very least, rule this out before replacing the PCM (unless you won't mind replacing the PCM only to have the exact same issue).
 
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skbishop90

Member
Apr 20, 2020
5
1
13
30
Birmingham, AL
I’ll try to make a long story short. This is my old high school car. I found it 12 years later and it remained 99% the same since I sold it. (Other than being small fender benders and pretty much every corner of the cAr now having something wrong with it).
I had a list of modifications done to it from when I had it before. Including a bank SCT chip with dial selector. I had 3 tunes: 87,93 and 93 with nitrous.
When I bought the car back about a year ago, the chip was still installed. It ran mostly “ok” other than a few weird quirks. Mainly egr codes and some weird chugging when coasting down or under very light throttle. I removed the chip and it ran “better” but still not perfect. I did a full tune up and got it running pretty good but eventually developed a problem idling. Honestly can’t remember if this problem started before or after I got the SCT X4 unit. I had a tune on it via the X4 before I did the cams. But ever since I did the cams, it obviously amplified the idling problem. Under throttle and WOT, it runs pretty dang good. And overall runs pretty good. Main concern is the idling.

sorry for the novel but I’m basically askingif anyone has replaced their pcm and how common a problem it is? And how can I verify the pcm being an issue?
 
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skbishop90

Member
Apr 20, 2020
5
1
13
30
Birmingham, AL
Do PCMs just "go out"? Or do they slowly go out and certain circuits start slowing failing? I have some weird issues with the drivability of my car but theres no error codes and its so inconsistent that Its hard to replicate to properly diagnose.