Well, so much for my theory about the GMS maf and the 93 tuning setting the SES light. See thread!
https://ls1tech.com/ubb/ultimatebb.p...;f=18;t=002540
When I put the truck back to stock, the SES light went out so I thought that was that. This morning I decided to check and see how the truck runs without any HPP tuning. I'm only using the raised shift points and firm shift setting on the HPP, along with the GMS maf. I only had about 15 miles on the truck and the SES light came back on, I guess it's a trip to the mechanic tomorrow to read the code. Oh well! On the up side, I did three 0-60 runs tonight and the truck is actually running quicker with out the HPP tuning. Before I got the GMS maf, the truck would run 0-60 in the 6.5 range using the old stop watch and the 87 HPP tuning. When I installed the GMS maf, the 0-60 time went into the 6.4 range. Tonight the truck ran a 6.46 (to much tire spin), a 6.21 (I think I was a touch quick on the stop watch) and a 6.31 (I was dead on the launch and stop watch reaction). The truck seemed to pull better in the upper rpm's, pulled better after the 1-2 shift. Maybe the HPP tuning and the GMS maf tuning fight one another. They did both help when used together but the truck seems quicker using only the GMS and no HPP tuning. I'm going to leave the HPP tuning out for a while and check it through a full tank of gas. I'll keep you posted.
Jim

 

The SES light went back out tonight on the way home from work. Now I'm confused! I'm back to thinking it was the HPP 93 tuning and the GMS maf. It took about 30 to set the light and it's been about 30 miles since I put the stock tuning back in. Could it take that long for the computer to correct the problem once the stock tuning was put back in? Now I guess I'll cancel the dealer appointment unless of course the light comes back on.
JIm

 

I had the code checked today and it was 1416, which is the "back bank of the air injection system. My mechanic said the more and likely it's a faulty O2 sensor. I checked at the dealer and the emissions are under warranty until 50K miles, so I'm still covered. I made an appointment for this Friday, I'll keep you posted.
Jim