automatic tranny causing occasional engine surge

[spudspuppy]

Hi all,

I have a 92 Silverado (198k on the truck). Engine and transmission have been rebuilt and generally runs great. Transmission has a shift kit installed and works really well most of the time. However, sometimes while sitting at a stop light, the engine will act like its under load and almost die and then surge back up to idle. It will do this several times in succession. I think the transmission is trying to engage, but doesn't get all the way there. If I shift into neutral, the symptoms will go away. Any thoughts?

As for the work done on the transmission, I don't have any details. I bought the truck used last year and the transmission had been rebuilt about 6 months prior. Shifts great and generally have no complaints except for this annoying bit.

Thanks,

Spudspuppy

[spudspuppy]

bump...

[KPVSR]

I would be willing to bet it is not the tranny. I have had two Fords that have done the same thing and in both cases it was the idle air controller.

[spudspuppy]

I'm not so sure about the idle...when it surges, it loads up the rear end when it does this, making the truck lurch a little. If I wasn't standing on the brake, I would go lunge forward....but then again, I could be wrong..

[broughy84]

Mine does this too.... That's the high quality gm Torque converter. Not putting gm down, when they work, they WORK, when they don't, they cause headaches like this.

[GMCMudBogger]

I have a 93 K1500 suburban that does the exact same thing, Initially the fuel pump went out & I thought it was this also, Changed the pump and it rans fine but still has the same problem your are describing, I have changed the Idle Air Control valve and Nothing changed, I changed the entire distributor, coil, cap, rotor, and the truck runs strong but still has this little annoying quirk about it, I was thinking of chaning the Fuel Pressure Regulator as a precaution. Also I have a B&M electronic shift kit, one that connects to the ECU.