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temporary malfunction question

Old 03-03-2017, 07:55 PM
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temporary malfunction question

On a relatively new to me 99 Trans Am. Started the car a couple of mornings ago and it would not idle. It kept trying to die and would drop below 300 rpm. I drove it about 20 miles. It ran poorly the whole trip. But it would maintain an idle without help after it got hot. When I would let off the throttle, it would drop to 500 rpm and then slowly climb to 750-800 rpm. On the drive home later in the day it started normally and drove normally. While it was acting up, it showed no codes. What gives with this? Thanks.
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Old 03-05-2017, 09:36 AM
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Re: temporary malfunction question

"It showed no codes" -- did you hook up a scanner, or are you basing this on no SES light?

If the latter, scan it and check for pending codes

Best guess:a vacuum leak, or a bad sensor somewhede. Keep driving it; it'll set a code soon enough and send you down the right path.
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Old 03-05-2017, 02:36 PM
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Re: temporary malfunction question

No codes was based on the lack of SES light. I have had a somewhat persistant knock sensor code, however.
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