C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

Rough idle

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Old Mar 17, 2002 | 07:48 PM
  #1  
akisana's Avatar
akisana
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From: Pearl Harbor HI
Default Rough idle

Hi everyone
I'm trying to find a message I posted, but it's taking a while. The original message concerns two problems I was having with my '89 automatic corvette. the first is rough idle whenever the car is in gear and the second is hesitation when I'm accelerating. I've tried cleaning the trottle body...also I had a mechanic check the onboard computer and the only error message I got, was that the MAP line or port might be clogged. I don't know what this is, so if anyone can help...pleease...I don't want to hurt my babe. thanx in advance
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Old Mar 17, 2002 | 11:24 PM
  #2  
85vet's Avatar
85vet
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From: Heidelberg PA
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Default Re: Rough idle (akisana)

Idle problems are a necessary evil of corvette ownership. Have you done a simple tune-up. Plugs, wires cap etc. One bad plug or wire can cause havoc!!!!

Have you checked your TPS (Throttle position sensor).

You can try disconecting MAF and if it runs good - it needs replaced.
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Old Mar 18, 2002 | 12:17 AM
  #3  
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From: Jacksonville Fl
Default Re: Rough idle (akisana)

the MAP line or port might be clogged
A bad MAP sensor or bad vacuum lines to the MAP sensor will definitely cause a rough idle and crappy performance.

I'm not exactly sure where it is located on the 91, but I think it's mounted on the rear side of the upper plenum, on the passenger side. If so, it has a 90º vacuum hose elbow that connects it's port to the vacuum port on the plenum beneath it's mount bracket.


[Modified by BBA, 11:20 PM 3/17/2002]
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Old Mar 18, 2002 | 02:44 PM
  #4  
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From: Nashville, Tn. 37211 TN.
Default Re: Rough idle (BBA)

If you haven't done so yet, I'd replace all the vacuum lines and boots on a car that is 11 years old. A small leak can really mess things up. About $20 worth of hose and fittings.
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