LT1 Engine Surges at Idle

[awatson]

My 94 coupe with an LT1 engine (auto transmission, 51,000 miles) occassionally surges from idle speed (approx 750 rpm) to about 1,300 rpm in hot weather and after it's warmed up. It's intermittant and happens only in warmer weather (say 80s +). Anyone have any idea what might be causing this? I'd like to fix it myself so any help you can give me will be greatly appreciated. Thanks!

 

[Ken]

Sounds like the Idle Air Control (IAC) is hunting. Seeing as how I don't have an LT-1 (or even an L-98 anymore :L) will anybody else hazard a guess?

_ken

 

[awatson]

Found the problem. The throttle body plate screws were loose causing an intermittent vacuum leak. Once I replaced the gasket and tightened them down the problem has not returned. Keeping my fingers crossed!

 

[Shadowing1985v]

what i think it is now,, i have ahd alot of problems with my car,,

im becoming a pretty good fixer these days

ususally if the car

raises its self in rpms by its self

or it back fires its probalby your timing

and if it surges at idle, its a vaccume leak
if u going down the road and some times u press on the pedal and nothing happends like your pedal is sugeing
its probably fuel filter

if the car misse's,, it could be igntion or injectors

if it doens't do any of these thing sand u have loss of horse power still probably o2 sensor
or cloged cat

 

[Karl Snedeger]

Don't forget the throttle position sensor. This will also cause a surge or bumpy idle.