Hoping someone in here might be able to help me out. My Dodge is currently in the transmission shop getting rebuilt, and I think my backup vehicle (my husband's '96 GMC) is feeling a bit left out.

About three days ago, we took it for a drive only to find that it felt totally and completely gutless when at WOT - the RPMs never exceed around 1500-2000, but with a decent hiccup it took off and started to run fine. Fast foward to today, and it's been doing it while I've been driving. From a complete stop it feels like I am trying to take off from a light with the parking brakes on - with the exception that the engine never attempts to rev up beyond around 2k. It feels like grandma going very easy in the throttle until we're up to full speed. No problems getting up to full speed. Playing around today, I manually shifted it and found it's not returning to 1st gear on it's own. Interestingly enough it's ok when going from park to 1st, but the instant the truck slows at a light, ramp, etc...it will not return to 1st without manually shifting the column down, then returning to drive after launch. Power still feels neutered, but not as bad as when it's trying to launch in 2nd gear. Doesn't feel like a 350 under the hood, more like a 4 cyl S-10.

No CEL on the dash, and trying to avoid paying my transmission guy any more money to have him scan the transmission unless absolutely needed.

Any insight?