Car runs awful until it warms up, then is fine.
07-11-2005, 05:38 PM
#1
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Location: Central Massachusetts
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Car runs awful until it warms up, then is fine.
My '96 Z28 has all the bolt ons such as pacesetter longtubes, true dual exhaust, msd 6al box, msd coil, obd 1 conversion by pcmforless.com, etc....
Anyways, when i first start the car in the morning or in the afternoon after work, the car will stumble and feel like its jumping from running on 6 cylinders to 8 or something like that. It has been doin this for some time now and I'm finally fed up with it. The car seems to run normal after it runs for a few minutes and heats up, i dont know if it has to do with entering closed loop(or open, I forget which one the car goes into when it warms up).
Sometimes it won't do it, like last week it was fine for a few days, but then it started doing it again.
Anyone have any ideas??
All help appreciated. Thanks.
- Adam
Anyways, when i first start the car in the morning or in the afternoon after work, the car will stumble and feel like its jumping from running on 6 cylinders to 8 or something like that. It has been doin this for some time now and I'm finally fed up with it. The car seems to run normal after it runs for a few minutes and heats up, i dont know if it has to do with entering closed loop(or open, I forget which one the car goes into when it warms up).
Sometimes it won't do it, like last week it was fine for a few days, but then it started doing it again.
Anyone have any ideas??
All help appreciated. Thanks.
- Adam
07-11-2005, 06:05 PM
#2
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Join Date: May 2005
Location: Grand Rapids, MI
Posts: 54
Re: Car runs awful until it warms up, then is fine.
I had that problem. Mine was fixed by simply tightening the screws on the air intake duct after MAF. Apparently the MAF was getting the wrong reading, making it run lean. When it hits closed loop, doesnt use MAF readings. Might as well try that, takes a few seconds. Hope that works for ya.
07-11-2005, 06:43 PM
#3
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Location: Phoenix,Az
Posts: 684
Re: Car runs awful until it warms up, then is fine.
When was the last time you changed the opti out? How about the O2 sensors are they up there in milage? Check the coil to see if its doing its job, even new they can mess up. Check the MAF just like 94lt1redta said, it might be something as simple as that. 
07-11-2005, 06:48 PM
#4
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Re: Car runs awful until it warms up, then is fine.
83,000 miles on the car, stock opti, new 02's in the front, dont have any in the back cuz its obd 1 now, how do i check the coil to see if its working?
07-11-2005, 07:00 PM
#5
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Location: Boulder, CO. USA
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Re: Car runs awful until it warms up, then is fine.
All of the above, plus fouled plugs?
I don't know about the Opti being the problem, though. Opti failures are usually relentless, and won't just go away under any circumstances.
-Goose
I don't know about the Opti being the problem, though. Opti failures are usually relentless, and won't just go away under any circumstances.
-Goose
07-11-2005, 07:22 PM
#6
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Re: Car runs awful until it warms up, then is fine.
ok i just went out and tightened the clamps in the rubber elbow after the MAF, which were kinda loose but the problem was still there.
i dont know what to think.
i dont know what to think.
07-12-2005, 06:57 PM
#10
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Re: Car runs awful until it warms up, then is fine.
jason kromer at pcm for less.com did it probably about a year ago. i honestly forget if the car started doing this when i installed the obd 1 computer with tune. the car has a lot done to it, nothin internal to the motor, but almost everything else that you can do.
07-12-2005, 07:09 PM
#11
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Re: Car runs awful until it warms up, then is fine.
Originally Posted by AdamZ1LE28
jason kromer at pcm for less.com did it probably about a year ago. i honestly forget if the car started doing this when i installed the obd 1 computer with tune. the car has a lot done to it, nothin internal to the motor, but almost everything else that you can do.
07-12-2005, 08:53 PM
#12
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Location: Chicago, IL
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Re: Car runs awful until it warms up, then is fine.
did you try disconnecting your msd box?? if not try it for a day or 2 and see if things change my msd would cause my car to not start, run rough, or it would stop firing cylinders at random.
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