I have a nelson tune. After about 5 pcm's and still getting KR, we switched to an 02 pcm. As soon as I put on the 02 my engine would die everytime I get ready to stop. Nelson thought it didn't take the upload properly so he sent me another one. Still doing the same thing. He wanted me to check for a vaccuum leak but I didn't find anything. When I first crank it up it idles fine. I have to hold the gas at 1000 rpms to keep it from going dead when I stop. My ltrims also have a big difference between both sides. At cruise its 15.6 and 0.0. At WOT its 9.3 and 7.2. Nelson told me that at 65 mph my timing should be between 32-40 but I only see about 25-29. I also lost 3-4 mpg going to the 02 pcm. Anybody got an idea whats causing this? I now regret not buying the hptuners and doing it myself. With how much I have already spent on shipping on 7 pcms and everything else I could have just bought the hptuners.

 

I just got my tune from him last week and had the same problem. I had the guys @ F-Body Central here in Baltimore do the install. After installing the PCM my 06 Denali did the same thing. The owner Jason plugged in his HP Tunners and noticed that the Nelson program would not hold a strong map sensor reading. He switched my map out with another truck in the shop and still the same reading. We put the old PCM in & it was back up to normal readings at idle. I think it should read in the 30's and the Nelson 1 was @ 13 - 14 on the map reading. He thinks it was a error in the pcm. Allen sent out another and bingo. Have someone check it for you, I also wish that I would of found this site earlier. I would of done a few things different.

Scott

 

Where is the map located? Is this something nelson would have to know in order to fix it because I already got a new pcm and it didn't fix it.

 

It's on top of the intake at the rear, since you have already tried so many pcms I think you might have something else going on. When I installed mine the truck idled really rough and you would have to hold the gas down to keep from cutting out. Jason said that it was a bad segment in the PCM. Mine started right up when the new pcm came. I would try to find a local shop that has Hp Tuners or EFIlive to check all your readings for you. I'm with you on buying the hp tuners, I just didn't know about all this till after I bought the kit. Good Luck and I hope this helped.