rough idle and pinging
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Joined: Aug 2001
Posts: 1,589
Likes: 2
From: British Columbia
Car: 90 IROC 5.7 hardtop
Engine: L98
Transmission: T5 swap
Axle/Gears: Yup -- they still work
rough idle and pinging
Hi All,
I have a '91 Formula LB9 TPI 5-speed with about 45k on the car and motor. Recently I've had some drive-ability issues fixed at the GM dealer, ended up with new plug wires and distributor, O2 sensor replaced. This helped alot (the car was in storage for 3 years) but a couple of weeks ago I developed a rough idle.
The engine shakes at idle but otherwise goes as fast as ever pulling strong to redline in each gear. My gas milaeage has dropped dramatically and the car shakes and bucks if I leave the clutch in till the last minute when stopping at a light.
The shake at idle is very noticeable but not radical, in other words it is very irritating but I can live with it for now. I figured I'd go back to the GM dealer but these guys always seem to fix 1/2 the problem but charge me twice what it is worth.
One more thing, the engine pings alot under load now. When I hit the gas in say 3rd gear, it pings then abruptly stops pinging. The whole time the car accelerates well. I don't see any clored exhaust coming out of the pipes -- it looks normal. Also, at tip-in, when you just touch the gas, the engine hesitates and has a slight mis-fire.
Any ideas ? Any of you guys seen this before ?
Thx in advance, RP.
I have a '91 Formula LB9 TPI 5-speed with about 45k on the car and motor. Recently I've had some drive-ability issues fixed at the GM dealer, ended up with new plug wires and distributor, O2 sensor replaced. This helped alot (the car was in storage for 3 years) but a couple of weeks ago I developed a rough idle.
The engine shakes at idle but otherwise goes as fast as ever pulling strong to redline in each gear. My gas milaeage has dropped dramatically and the car shakes and bucks if I leave the clutch in till the last minute when stopping at a light.
The shake at idle is very noticeable but not radical, in other words it is very irritating but I can live with it for now. I figured I'd go back to the GM dealer but these guys always seem to fix 1/2 the problem but charge me twice what it is worth.
One more thing, the engine pings alot under load now. When I hit the gas in say 3rd gear, it pings then abruptly stops pinging. The whole time the car accelerates well. I don't see any clored exhaust coming out of the pipes -- it looks normal. Also, at tip-in, when you just touch the gas, the engine hesitates and has a slight mis-fire.
Any ideas ? Any of you guys seen this before ?
Thx in advance, RP.
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