Thread: DHP v1.0 ststststutter @ 4500rpm in 2nd.

Did you do a case learn after installing the pcm? It's a must most of the time. You could be getting kr that your not seeing cause your not scanning.

IMPORTANT: If you are installing a reprogrammed PCM, make sure to take the car to the dealer to get the crank sensor position (or CASE) learned. This is not required for 1997 GP PCMs because the data is already stored in the knock sensor you switched above. You may get a "Service Engine Soon" lamp after the installation - this is due to the CASE learn not having been performed. Whether you get the SES light or not, you should still get the CASE learn procedure performed. Any GM dealer or official service shop can do the procedure if they have a Tech2; they may charge you a nominal fee for the service. In brief, here is a description from the GM Service Manual:
The crankshaft position system variation learning feature is used to calculate reference period errors caused by slight tolerance variations in the crankshaft, the crankshaft balancer interupter rings, and the crankshaft sensor hall effect switches. The calculated error allows the PCM to accurately compensate for reference period variations. The crankshaft position system variation learning feature enhances the ability of the PCM to detect misfire events over a wide range of engine speed and load.


Need to either take it to a dealer, or have someone with a tuner do it for you.

Case learn is important if swapping pcm's. Like posted above go to the dealer or find someone with a tuner and they can case learn the car. I'd suggest staying out of the throttle though till.