sam_ls1

I recently purchased a 2001 LS1 from ebay and installed it in a 1990 Silverado. I also purchased an ECM from ebay and had the VATS and the rear O2 sensors removed. When I went to start it and fired up and quickly died. I did this a couple of times and finally got it to run. But the idle was rough and it would stall when I would put it into gear. I first thought it was an engine problem and did a compression test, checked for vacum leaks, etc. Somebody told me to try the orignal ECM that came with the engine and it ran perfect. I sent the ECM back that I got from ebay and they checked and out and told me it was fine. Do I need to get a crank relearn done on this ECM? Would this cause the rough idle?

eseibel67

iTrader: (10)

That is normal. The PCM is learning how to idle. Turn the AC on and off in gear and in park several times to speed up the process.

And yes, you should do the CASE relearn.

Frost

iTrader: (45)

I would think it would be hard to say that without knowing what was dumped into his eBay PCM....