running rough after warm up
Thread Starter
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Joined: Oct 2004
Posts: 70
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running rough after warm up
i have a 93 A4 LT1 with 30K. Can has never seen rain or wet pavement. When the car warms up to over 190 the idle becomes rough, and just about stalls. If I put in neutral and rev, it stumbles, and I sometimes hear back fireing through the exhaust.
Does not throw any codes...
It runs great till it gets warm....
Anyone elso have a similar experience?
Does not throw any codes...
It runs great till it gets warm....
Anyone elso have a similar experience?
Melting Slicks
Joined: Jul 2000
Posts: 2,107
Likes: 14
From: Lancaster PA
My 94 acted that way a few times this past summer but only if it reached 230 or more. I've since put in manual fan switches. Today I drove it for the first time in 2 weeks and it ran great until I let it set for 20 minutes while I was in the store. When I went to leave it would barely run. It back fired and stalled. I had it towed home and after cool down it runs good again. I'm thinking time to replace the OPTI.
Thread Starter
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Joined: Oct 2004
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I was thinking the exact same thing...Opti. I would like to understand why they operate fine when cool, but act up after they get to engine temp.
does any one know why they fail, and why they run fine when under 180?
does any one know why they fail, and why they run fine when under 180?
Team Owner
Joined: Aug 2000
Posts: 40,156
Likes: 45
From: San Pedro CA
that's why I don't want to think its the opti. I would expect some codes if it was.
You see, at 190*, the computers will slip into closed loop - meaning the computer is reading sensors and adjusting things accordingly.
however, everytime I have seen this, it has been related to the optical side of the optispark...
check the coil and ignition module... they are noted to fail. and the coil is heat sensative.
You see, at 190*, the computers will slip into closed loop - meaning the computer is reading sensors and adjusting things accordingly.
however, everytime I have seen this, it has been related to the optical side of the optispark...
check the coil and ignition module... they are noted to fail. and the coil is heat sensative.
