i just put together a 90 3500 crew cab ,454tbi ,th400, np205, rockwells, 4 wheel steer, 14.9x24 v treads. this is my first tbi truck and it seems to idle rich and run rough up to 2500rpm , then cleans up and runs fine. if you stab it to the floor in gear it is lean and pops back in the throttle body. any suggestions would be great .

You should learn to log data from the ecm on a laptop.
You can make a data cable for less then $10 and the software is free(winaldl).
Then just go for a drive with the laptop hooked up and it will give a good idea of how your engine is running and your Air Fuel mixture.

I have all the stuff needed listed in the FAQ's in my sig.

Look for how to read and change data thread.

You didn't mention the ECM number but if it was original then it should be a 1227747 or 1228747.
The 7747 is the more common ecm.