Engine Performance problem
1999 Chevy Suburban V8 Four Wheel Drive Automatic 172000 miles
My Suburban is giving me a some trouble. When starting out down the road everything is great until I hit about 40-45 mph then it starts bucking, or hesitating. This lasts until I hit about 55 mph. If I gun it it won't hesitate. Once I am past 55 it runs out fine. Seems to only be an issue when applying the throttle gradually. I have replaced the plugs and wires, just replaced the starter (was told this issue could be starter related), and have run Berryman B-12 through the fuel system. I am at a loss of what to try next. Sure could use some help.
I am having same issue, mine too is a 1999 chevy suburban, just hit 117k miles. It has random bouts with trouble starting. Hesitates at different speeds. After about 20 mins of driving you will hear and feel a thunk from rear of vehicle.
October, 12, 2012 AT 4:10 PM
Trying to solve the same problem. No answers for you, but if you found a solution please share! My question title, if you search for it, is "1998 Chevrolet Suburban My K2500 Chevy 7.4L runs fine cold."
October, 13, 2012 AT 1:41 AM
SOUNDS LIKE THE T.P.S. THROTTLE POSITION SENSOR IS WEARING OUT.