Well ever since I did the GM supercharger flash on my Cavalier the Low 1 and Low 2 gears wouldn't work right. Then came the random codes, misfires when it felt like it, and sluggish performance. So After much thought I came to the conclusion that the PCM may be shot. Hence I ordered a reprogramed used one for my VIN with the GM Flash again. Got it in the mail today, installed it, and began the PassLock relearn procedure. First thing to catch my attention was that the THEFT SYSTEM light only stayed on during the first cycle. The following two cycles it was no longer there. After the third cycle the car started fine and then gently began to lean out during idle and die, just like during the relearn cycles. If I hold the gas it will stay alive. After a while I can drive it down the street normally, but if I give it hard gas (50% or more) it falls flat on it's face and when it does pick up it is running completly leaned out to the red (--- on my AEM). After a while I'll get a P0171 for Bank 1 Lean and the car will go into limp mode. But now Low 1 and Low 2 work, lol. Now if I put the old PCM back on it runs like before, normal, but no Low 1 or Low 2.

Could this PCM be shot? MAybe it wasn't set for my VIN? Did I screw up the relearn procedure?
Any input qwould be great. Thanks guys for reading.

Just to clarify a few things:

Installed used reprogrammed/recalibrated PCM for my 2003 Cavalier Automatic with GM Supercharger Kit and Flash
Car starts but shortly dies after 3 seconds max.

There is gas in it. My support is that the gauge says it, I've been able to drive it up and down the street, and fuel pressure is constant.
Fuel pressure is at 50 - 60 psi and stays there even after dying
Vacuum is at 20 hg until it begins to die (10 hg), and then dies (o hg)
AFR is at a nice 14.x:1 during the first few seconds and then drops to 17.x:1 and finally --.-:1 before dying
No THEFT SYSTEM light is on before, during, or after it dies.
Interestingly the THEFT SYSTEM light does stay on while cranking the engine
Also when it dies the DRL relay clicks and my cluster shows the DRL symbol illuminate for a second
Car will not even idle for a second after it dies the first time, have to wait a few minutes in between or crank it three times
I've done the PASSLOCK Relearn 3 times tonight. Only the first time within the first cycle did the THEFT SYSTEM light stay on as the instructions say. Every cycle and time after that it was never there.
Car can be maintained on with a little extra throttle, but under acceleration or boost it falls on it face.
Reinstalling old PCM makes the car run fine as before
Only CEL is a Bank 1 Lean after driving it a while

Our cars ECU's do not have a limp mode.

Any other codes in the ECU?

What is fuel pressure when this happens?

Do you happen to have a exra TPS sensor laying around you could swap in?



FU Tuning

Well limp mode to me is when the TRAC OFF light stays on, the cooling fans stay on, and the transmission shifts like it hit a wall. Usually does this when there is a hard code fault or sensor fault (i.e. TPS sensor)

No other codes, just the Bank 1 Lean

When this happens it's anywhere between 50 - 60 psi

I might, got to find it first through all my spare parts, lol

Sounds like a vaccum leak...... which would explain the lean condition very well..... Have you check the vaccum reading on the engine?

No vacuum leak. Gauge is at 25 hg at idle.

I had the old PCM which was acting dumb (Random codes, transmission shift problems, etc.). Replaced it with a new PCM calibrated to my VIN and GM Flash and that PCM is the one causing the car to run poorly. Cured the problems of the other PCM, but now the car won't run right. If I switch back to the old PCM, the car runs like before. That's why I was wondering if there is more than the PASSLOCK Relearn that needs to be done when replacign the PCM.

hmm.. there has to be more issues that do not point to the passlock, what do you mean it runs like crap... are the fuel specs spot on and there are no codes???

Well I have to play with the gas pedal to just keep it alive. Afterwards it'll stay alive for a while, but as soon as it goes in gear it dies and has no power. This whole time the AFR are super lean ( --- on the AEM gauge). Some more fidgeting of the pedal and the car can drive. As long as there is no boost it may stay alive, but once boost hits, it falls on it's face, no power, no power, and then suddenly it will have some power, but will be running super lean.

Only codes are P0171 for bank 1 lean and I forgot the number for the other, but it just says lean while accelerating.

I need to get a good working computer.

Btw in the time since I was last one her I took it to the dealer to get checked out and maybe reprogrammed there. They said the new PCM should work, but they don't understand why it doesn't. The recommend I get a new one from them for $600.

you have had nothing but issues with this car since the first post i ever read of yours. I am going to venture that it might be something you over looked or did incorrectly during the initial install. wires spliced wrong or something. a vacuum line pinched, or not hooked up. something.

although most people will think this is RETARDED!!!, i am going to suggest tearing the whole (mechanical parts anyways) supercharger system off, and re installing just to make sure you did everything right. go over every electrical wire you touched, hell even the ones you havent, and make sure it is right, go over every vacuum hose that needs to be hooked up and make sure it is right. check all your grounds, everything. I know lots of people with the blower, and you are THE only person that has had these issues over and over and over and over and over.

^ bazinga

Agree with EvoFire.

I tore apart the whole engine back in November when I switched transmissions to see if that solved my Low 1, Low 2 problem. Didn't happen. Pulled the Charger off, both manifolds, valve cover, timing chain cover, oil pan, etc. Two weeks ago I dropped the engine and switched transmission again due to problems with the LSD. Everything checked out and was fine. Still has the same symptoms.

I am almost 100% sure the problem lies in the PCM. The new PCM I got solved all my transmission and engine problems, except at boost, where it was fuel starved. So I am further convinced that the PCM is behind all this.

Another thing is that my current PCM calibration # is a random sequence of letters and numbers instead of all numbers. The guy who programmed my new PCM said that calibrations never had letters in them. Can anybody input on this?