1996 5.7l Stumbles Off Of Idle

Drastic396 · May 29, 2008

Recently, I replaced the intake manifold gasket on my 1996 Suburban 5.7 - it had a water leak. While it was off, I cleaned with carb cleaner and soap and water. The car now stumbles (bad)when accelerating off of idle. It also shutters when the converter locks or OD engages. There are no vacuum leaks and the TPS checks ok. I changed the fuel filter while trouble shooting this issue. There are no DTC's or other obvious problems. What should I check next?

95Sierra2500 · May 29, 2008

Check to make sure you didn't damage your fuel pressure regulator. You may want to get your injectors cleaned as well, as if you've got something clogging the poppet nozzles you could have a serious issue with that.

L29er · May 29, 2008

Probly not the cause but you could clean your MAF sensor, use a aerosol that doesn`t leave a residue (usually and cleaner that IS flammable leaves no residue)

Drunken Sailor · May 30, 2008

Did you pull the injectors (spiders) out of the intake? If so, did they go back in the right place? If I remember correctly (and this might not make any sense) the tubes on the inside of the central injector go to the furthest away holes, and the ones on the outside go to the closer holes. They sort of cross eachother I think. Sorry, it's been a while since the last intake on a Vortec. They seem to be much better than the TBI engines.

Drastic396 · June 4, 2008

Thanks for all the replies. Here is an update. The fuel pressure was ok. I put another TPS that I had and that cured the stumble. On the other issue, I think either the TCC or the torque converter lockup is having problems. At lockup the car shudders hard. The other day, the car stalled when we came to a stop. Any hints on trouble shooting the torque converter solenoid or the converter itself?