1999 Chevy Tahoe When going up slight incline truck misfire

CLEVELAND17

MEMBER
1999 CHEVROLET TAHOE
V8
4WD
AUTOMATIC
98,000 MILES

I've had a number of shops tell me that the problem ranges from needing a tune up to the transimission is shot. The Servie engine light comes on and when it is checked by the shop they tell me cylinder #4 is misfiring. Could be injector (the engine is throttle body, I think) or intake manifold. Why doed the light go out and return only when I put the truck under a slight load. I notice that when I get to 2k rpm it begins to act up. When I come to a stop the truck runs rough then smooths out. If I really stomp on the gas the truck nearly stalls out completely. It takes a few minutes of rough running then returns to normal idle.
I've done a complete tune up, wires, cap, rotor, plugs, air filter. Trans oil ad filter changed because I thought it started feeling like the tranny wasn't going to low idle.
I read forums and it sounds like very similar problems are reported and it is suggested to replace the "shifting solenoid"? Need help, I love this truck and it seems I am missing something simple but so is the garage.

1 Reply

PEAR69

MECHANIC
1,482 POSTS

First you must test to see what the fuel pressure is. Then we can take it from there. Your symptoms are not uncommon. It could be several things - fuel pump - fuel pressure regulator - timing issue - electrical issue. These engines must be running right in order for the transmission to work properly. Many people jump to the conclusion that the tranny is bad when is reality the engine is running poorly causing transmission symptoms.