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Rough Idle please help!!!!

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matt98eclipse

15+ Year Contributor
1,078
0
Aug 15, 2006
mesa, Arizona
I have a 91 gsx completly stock other then some free mods i did! I just bought the car about 1 month ago and and the car doesnt idle right. It sounds like it has a little misfire. So today i went and change the oil,spark plugs and spark plug wire's and the car seems to have ALOT more power!! But the car still have a misfire at idle, when im driving slow u can feel the car kinda sputter!! Please help guys!! Any one got any ideals????

p.s. When i first start the car the idle goes way up to 2000 rpm's then when warm's up goes back down to around 850 rpm's?? normal

sorry guys new to the 4g's
 
If your BOV isnt recirculated then the idle may jump high and stay high til you blip the throttle. Check your spark plugs and make sure they are the right kind. I once bought too powerful a spark plug for my RS and they fouled out in a matter of days. Sounds like what you are experiencing.
 
Your unstable idle could be because of your free mods. If you removed any vacuum lines from your throttle body and did not seal them or took the tb off and did not make a good seal for the gasket, you may be letting unregistered air into your intake and the isc motor is not compensating causing shaky idle.
 
Your ignition timing could be advanced a little much for your boost level causing the misfires at idle or you could have low compression in a cylinder causing the spark plug to ignite premature or late.
 
I personally would not drive it intill the problem was fixed but, if you really need to drive it should be okay.
 
UPDATE:

earlier this evening I hooked up a boost gauge. The car boost at around 8 or 9 pounds so I think that's ok? I knoticed when i do a cold start the motor's rpm's bounce between 2000 and 1500 for about 5 minutes! So I turned on the ac to see what happen's and the rpm's stay right at 1500!! Once the motor is wormed up it does a steady idle right around 850!!! What do u guys think???
 
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