rough idle on 1998 Chevrolet Tahoe

Example: Sitting at stop lite.Idle starts to run rough in drive position,but when gear is moved to either neutral or park, runs smooth.

by in Reston, VA on June 21, 2011
1 answer 2 comments
ANSWER by on June 21, 2011
sounds like a plug or coil failure. you need a shop to verify and give you a bid. Roy
1 person likes thisFlag inappropiate
COMMENT by on June 21, 2011
What do you mean by a coil failure?
COMMENT by on June 21, 2011
ignition coil. there is one for each cylinder and it could be failing by not firing the spark plug. Roy
Related Items:
Already replaced spark plugs, wires, cap & rotor, oil & filter. Symptoms remain: rough idle, shaking, rich exhaust smell. Going to replace the intake gasket next. Need to fix before May...
why does my engine run rough when it rains or moisture in the air
123,000 miles. Engine idles rough at cold start unless I increase to 1500 rpm for 1-2 minutes, then fine. Replaced plugs, wires, filters, cleaned fuel system, yet problem persists. Any suggestions?
A dirty throttle body may cause a lower than normal idle and possible stalling condition. Performing a throttle body service will commonly correct this concern.