Ok, so I have a 1982 s10 with a 355 and a th350 tranny. I bought it as a project and it sure has been... I've had trouble with timing, trouble with the carb tuning, trouble with the rocker arms and everything in between.. The engine was supposedly fairly fresh but I think whoever did the work should have their toolbox confiscated and dropped on their head... everything was Jimmy rigged... I have most of the bugs worked out now but now I have a new problem... When I hammer the gas in first gear it's almost scary, it buries you in the seat and goes like hell... it makes great power then it has a good hard shift where it usually barks the tires again then it goes gutless and the rpms just creep up in second gear. It almost feels like it's skipping second gear and jumping straight to third... Any ideas what would cause this? Like I said this is new, before I did the intake gaskets and fixed all the vacuum leaks this was not an issue...

 

there is one hard line (I swapped mine for fuel line for easier maintenance) that goes from the MANIFLOL vacuum tree to the vacuum solenoid on the back of your TH350, make sure that is hooked up, if that does not fix the issue at hand, next I will say it could be a valve body issue. Someone might have tried an at home "shift kit" leading to this. hope this helps.

 

Maybe it is jumping to third gear. But sounds like a fuel supply problem. Pump giving up, clogged filter, floats too low, etc.

 

I wouldn't replace the hardline for the modulator. The hardline doesn't collapse and rob vacuum like a hose will. Not that it won't work I've just seen issues in the past. I wonder if it could be a stuck check ball causing issues with the hydraulics.

 

Manually select 2nd and see if the problem continues. If it does, carb. If not trans.