I'm back! My '88 cherokee (5-sp. straight-6) has a new (rebuilt) engine and clutch. Everything is great except: After starting, the motor idles great and when pushing on the gas, it revs up smoothly - until I put it in gear. Then it stutters consistently as I go through the gears and will even backfire a little. The problem lessens when the motor is nice and warm. Problem does not occur if I am in neutral, cold engine or not. Anyone have any ideas? I don't want this one little problem to screw up my relationship with this re-born Cherokee. Thanks for past help and thanks in advance on this problem!
V/R - Gonzo 1SG

 

Sputtering under load (neutral/park doesn't load the motor) could be a basket of things, vacuum leak, marginal ignition components like plugs and wires, bad fuel pressure, incorrect timing or mixture due to a failing sensor..
Has it done this since it was rebuilt? Pulling/reinstalling a motor is prime time to crack or break old vacuum lines. I'd probably start there.

 

Where the 3 wires ground at the dipstick tube stud, did you clean that point to bare metal or does it have coats of paint on it? Are the wires even hooked up? They can get "lost" in an engine swap.

I would also click on the link in my signature and read post 13.