Run' rough at Idle, please help
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Joined: Nov 2001
Posts: 117
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From: Macomb MI
Run' rough at Idle, please help
I have tuned up my 87 vette, however once warmed up it runs rough, feels like it wants to die but keeps running.
New wires-Auto Zone Ultra Spark Double Silicone US made
Plugs-AC Delco
Cap and rotor Borg Warner
Tried two cans of fuel injection cleaner
I have burned three tanks of 92 octane shell gas this spring.
Replaced the intake manifold gasket last fall, and new water pump this spring.
The car is stock with no modifications. I want to modify it but I would like to solve the rough idle problem first.
I removed the radiator last week and cleaned it.
Does anyone have suggestions on what to check? I am frustrated to the max!!!
Jim
[Modified by jimbo10494, 7:09 AM 6/12/2002]
New wires-Auto Zone Ultra Spark Double Silicone US made
Plugs-AC Delco
Cap and rotor Borg Warner
Tried two cans of fuel injection cleaner
I have burned three tanks of 92 octane shell gas this spring.
Replaced the intake manifold gasket last fall, and new water pump this spring.
The car is stock with no modifications. I want to modify it but I would like to solve the rough idle problem first.
I removed the radiator last week and cleaned it.
Does anyone have suggestions on what to check? I am frustrated to the max!!!
Jim
[Modified by jimbo10494, 7:09 AM 6/12/2002]
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Joined: Jul 1999
Posts: 741
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From: Eagle IDAHO
Cruise-In I Veteran
Cruise-In II Veteran
Re: Run' rough at Idle, please help (jimbo10494)
Jimbo, What your car is suffering from is quite common on our ol L98s, mine included.
Possible causes: Intake air leaks. Diagnostic tool. I took a propane (Bernzo-matic torch) and attached a two foot piece of small rubber hose to the nozzle. While the car is idling, direct a slow flow of propane gas (not lighted) over all the possible points of intake air leakage. If the idle changes at any point of this operation, you have found a leak. Don't stop at finding only one leak, you may have others.
Bad MAF: Diagnostic. While the car is running, disconnect the electrical connector to the MAF. If the idle improves you may have a bad MAF. Before buying a new one, see if you can swap with someone who has a good MAF for a check.
TPS adjustment: See Tech Tips this Forum
Carboned up Throttle body: Remove and clean.
IAC plunger carboned up: Same as Throttle Body.
Finally, run a search with this topic and you will see lots of us working on the problem.
Good Luck
:seeya
Possible causes: Intake air leaks. Diagnostic tool. I took a propane (Bernzo-matic torch) and attached a two foot piece of small rubber hose to the nozzle. While the car is idling, direct a slow flow of propane gas (not lighted) over all the possible points of intake air leakage. If the idle changes at any point of this operation, you have found a leak. Don't stop at finding only one leak, you may have others.
Bad MAF: Diagnostic. While the car is running, disconnect the electrical connector to the MAF. If the idle improves you may have a bad MAF. Before buying a new one, see if you can swap with someone who has a good MAF for a check.
TPS adjustment: See Tech Tips this Forum
Carboned up Throttle body: Remove and clean.
IAC plunger carboned up: Same as Throttle Body.
Finally, run a search with this topic and you will see lots of us working on the problem.
Good Luck
:seeya
Le Mans Master
Joined: Nov 1999
Posts: 8,512
Likes: 3
From: Memphis, Tn
Re: Run' rough at Idle, please help (jimbo10494)
Here's what helped mine:
2 bottles of Techron (fouled out plugs).
Remove and clean the throttle body and IAC valve.
New plugs.
Idle was improved, but still not right.
Next I replaced the valve springs (and seals). Now it idles about perfect. Apparently the old springs were weak.
2 bottles of Techron (fouled out plugs).
Remove and clean the throttle body and IAC valve.
New plugs.
Idle was improved, but still not right.
Next I replaced the valve springs (and seals). Now it idles about perfect. Apparently the old springs were weak.
