mrws6speed

Here's the situation.

I just picked up a '91 T/A WS6.
When I start the car, the Service Engine light will be on and the car will want to die. After about 10 seconds or so the light will go out and the car will start running right at exactly the same time the light goes out.
While the service engine light is on or when just turning power on, the scanner will not communicate w/ the ECM.
As soon as the Service Engine light goes out when started, the scanner can talk to the ECM.
The Error code is 51 (If I remember correctly..maybe 53?) which is ECM PROM Error.
It does not seem to happen when the car is cold. As the car gets hot it gets worse (sometimes the Service Engine light never goes out and the car eventually dies despite giving it gas to keep it alive).
I replaced the Computer (Not the Chip) with a reman from Autozone. No change.
The car has an aftermarket stereo which I'm not sure how they have it wired up.
The car has an aftermarket Remote Keyless Entry (not alarm), which I'm also not sure about the wiring yet. I'm going to be digging throught the wiring next to figure out what they did.
When it doesn't have that ECM Problem, it runs like a bat out o'He!!
Thanx, Mike

xtremeirocz

have you tried checking the prom, maybe change proms and see if that helps, it might be intermitten or only once the prom is on for a while will it act up, i had this same issue on my 89 and i put a stock prom from gm in there and the car ran like night and day