When I am coming to a stop, my engine will rev up about 300 to 400 RPM's, causing the truck to lurch right before it stops. It just started doing this recently. The transmission was rebuilt by GM a few months ago. Does anyone have any suggestions or thoughts as to what could be causing this? I can't tell if it is just revving, or if it is downshifting, but it happens at about 5mph or less. Any thoughts would be greatly appreciated. Thanks.

 

What was the reason for the rebuild? Did the dealer rebuild your existing tranny or replace it with a factory rebuilt tranny? Rebuild should be under warranty from dealer, I would return to dealer first and have them check if there are any stored codes in the computer.

 

Mine does this, but it is due to the ported TB and me adjusting the blade to get it to idle with my cam. I believe the IAC needs to be adjusted in the PCM to correct for it, but it just doesnt bother me enough yet to do it.

 

The clutches were burned up. It was covered under powertrain warranty. I believe that they rebuilt my existing tranny.

 

ttt. anyone else with suggestions?

 

im thinkin it may be the tune...mine did this when my tune was off a bit then i fixed it and it stopped

 

Mine does the opposite, it tries to stall when I am coming to a stop. I did a little bit of research on it and I think it has something to do with the desired airflow tables in gear and low RPM. Run the truck up to like 10 or 15 mph, put it in neutral, and see what the RPM's do. I think I recall reading that if the RPM's bounce up and down (like mine do) that the desired airflow tables need some work. Although - I don't know why your tables would have changed from stock if you don't have a cam.

Maybe try giving Jesse a call and see if he knows anything about it.

 

When I put it in neutral at 10-15mph, the rpm's go from 1000 to 500. When it is in gear, it tends to idle at around 1000rpm, which I don't remember it doing before.

 

Throttle cracker!

 

Hmmm, check the vacuum line? I know a mechanic switched the vacuum lines on our 95 cutlass and caused it to lurch, but we only have one line coming out of the housing... just a thought?