I have a 1989 G20 and when I'm driving uphill, I feel like the van is struggling. Like it lags and goes in and out of this jerking feeling. The gas level is between a quarter to half. A mechanic couldn't find anything wrong with the transmission or carburetor... I've had a full tuneup in Sept. Any idea what is happening and what I might be doing wrong? As far as speed, I was going 40-50 mph...

 

Sounds like the torque converter locking and unlocking and maybe shifting between 3rd and OD. Just shift out of OD.

ETA: if you want to see if it is the torque converter or not gently stepping on the brake pedal with your left foot will unlock the torque converter.

 

Thanks! My van has been in the hands of a mechanic and they haven't figured out what is causing my uphill issue. I will have them take a look at the torque converter. Thank you for your input!! Happy New Year

 

A 1989 shouldn't even have a carburetor, they were throttle body injection. Bad MAP sensor can cause this and not set a code. Gotta take the doghouse off to get to it.