ok
along the main wiring harness under the floor plate where it runs along the engine look for a 4 prong connector, it will be a square connector marked with letters A B C and D. You need to cross the A and D terminals and turn on the key switch. When you do this it will flash any stored error codes (if any).
- turn on ignition but do not start engine
- the MIL will start to flash, you will first get a 116 code telling you it is in diagnostic mode, then it will flash the error codes... once it gives you all the error codes then it will pause and start over with the 116 code and repeat the error codes.

to erase any codes remove the F1 battery fuse for more than 15 seconds. This will erase all memory in the computer including the adaptive learn.

do this and see if there are any errors that may not be lighting up the MIL.

let us know what you find

remember ultimately you may have to get the PSI software and connect with a laptop to see what is going on.

the serial# is AT8701976.... CHECK ENGINE LIGHT IS NOT ON

no serial number ?
like edward says, we need that
other than what edward was asking...

is the check engine light on?

I am SOO tempted to say "call my friends at Ringlift", but that would be rude, so...first thing will be to post an accurate serial number, and then make sure the accel pot is connected and not out of adjustment, also check to see that the wire to the transmission speed sensor is connected. It is the bottom most wire on the truck, and sometimes gets pulled off from driving over trash or debris, just look under the truck and make sure there is no wires hanging disconnected.