L98 occasional erratic idle
Thread Starter
Melting Slicks
Joined: Jun 2008
Posts: 2,853
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L98 occasional erratic idle
Hello
I pondered this and thought this forum may be the best place to find an answer to an issue. I realize it's a Camaro, but it has a similar engine to the C4 of its time and this is my fave forum.
I have an 89 Camaro IROC with a 5.7 litre L98 TPI 71K miles.
Most of the time when I start the car it starts and idles great. About every 20th start it fires, idles very rough and the tach jumps around. I just shut it off restart and it then runs smooth.
It gets good gas, has clean air filters and has had a good service history.
Any suggestions on where to start trouble shooting will be appreciated.
I pondered this and thought this forum may be the best place to find an answer to an issue. I realize it's a Camaro, but it has a similar engine to the C4 of its time and this is my fave forum.
I have an 89 Camaro IROC with a 5.7 litre L98 TPI 71K miles.
Most of the time when I start the car it starts and idles great. About every 20th start it fires, idles very rough and the tach jumps around. I just shut it off restart and it then runs smooth.
It gets good gas, has clean air filters and has had a good service history.
Any suggestions on where to start trouble shooting will be appreciated.
Safety Car
Joined: Aug 2013
Posts: 4,429
Likes: 605
From: Minneapolis Mn
Does the service engine light come on at the same time? Sounds somewhat like one I've tried to track down - DTC41. I suspect that it may be a bad or weak ground somewhere. I've had little luck getting under the car to check them out, I'm thinking about renting some time on a lift to make it easier to check.
Before doing any parts throwing, see if you can get it checked for any existing codes. That and a FSM are invaluable additions to your diagnostics.
Before doing any parts throwing, see if you can get it checked for any existing codes. That and a FSM are invaluable additions to your diagnostics.
Racer
Joined: Apr 2013
Posts: 435
Likes: 4
From: Guilford NY
I would start right at your ignition components. Look at your dist cap and rotor. If a tach is jumping around, it usually means something is arcing. Lots of voltage around the dist, and the tech gets its signal off the coil neg. If you have improper arcing in the cap, it will feedback to the primary of your coil. HTH,
Mike
Mike
Safety Car
Joined: Aug 2013
Posts: 4,429
Likes: 605
From: Minneapolis Mn
I had a tuneup done last Friday on mine. I had the dealer do it along with a couple of other things and wasn't sure how long the old plugs were in the engine among other things.
So far it's running fine but when the 2 times the SES came on and got the codes, it's was 25 degrees out which may be a factor.
We'll see if that takes care of it or not.
I'm still wanting to get it up on a lift and clean the grounds etc up onit.
So far it's running fine but when the 2 times the SES came on and got the codes, it's was 25 degrees out which may be a factor.
We'll see if that takes care of it or not.
I'm still wanting to get it up on a lift and clean the grounds etc up onit.
