I just finished putting a 2004 5.3 into my 2001 RCSB Silverado. I am going to use you for the tune but I was wondering if you know of anything special that you would have to do to make a 2004 engine work in a 2001 truck. Such as learning the instrument cluster to the new PCM, etc.

My problem is I have no PRNDL display and the truck will crank but will not start. I have spark and fuel. I have the TAC module and pedal hooked up and working. I have the fuse block connector repinned to the best of my knowledge according to the diagrams. I intstalled the complete fuel system from the 2004 (fuel lines, tank, and pump).

I guess my question boils down to this: Do you have to change the VIN in the PCM and take out the VATS for this to work? Do you have any experience tuning a 03-up PCM to a 02-down truck?

I want to get the tune from you but I don't want to waste either of our time if it won't help anything. Thanks in advance for any help or advice anyone can give me.