Every time I write a new tune to the PCM I go to start it and it wont stay running. You try to start it a bunch of times and feathering the throtle and it eventualy snaps out of it. I schedule time to Dyno today at edge and we got no where because of this. One other problem I can not put it back to stock. I use to do mail order tunes through nelson performance and eventually had him send me a stock tuned pcm but It cam back for a long bed with the wrong VIN. I cant even change the VIN to the correct one with a techII. Any help would be great. also it does this wether I change the tune or leave it the same. I can reload the exact same tune that runs it does the same thing. One other thing if I try it on high speed it fails.

 

You should only be flashing the pcm not doing a complete overwrite.
It sounds to me like a physical engine problem not tuning if you have the same issue regardsless of tune.
Call nelson and have him swap the pcm for your correct vin.

 

I meant reflashing. If he sends me a pcm with the write vin I will have to re-license it right?

 

If you licensed a single vcm then your are licensed to 1 vcm, if you are swapping between several vcm's you will need to have a license for each one as you are NOT licensing the vin number & rather the serial number in the pcm which is unique to each pcm.

 

How about the starting problem after the re-flash? Maybe a vista problem?

 

What are the symptoms? Does it fire and die? Or no fire at all? Or start and idle really rough and die?

My first guess is that the idle airflow tables are way off and it takes some time to relearn the idle trims. Are you running a large cam by chance?

 

Sounds like a tuning issue or mechanical problem.

 

It fires and then dyies and if you give it some gas it will stumble a little longer then dye. Sometimes it wont snap out of it and I re-flash the same exact tune and it will eventually snap out of it. I cant even put the stock SD tune back into because it will do the same thing and not snap out of it. Stock cam Idle air flow tables are not changed.

 

this may sound stupid but check your negative battery cable connection at the battery

last week i had a 2004 2500 sierra come in, did an intake on it and it would start and stall and only run if i featherd the throttle for like 5 minutes, it a whole day to find the weird terminal block the guy had installed on the negative cable was loose, tightend it and the truck ran great

 

I already checked the battery connections and the current charge and condition. It has two yellow top optimas.