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bobtodd · 05-11-2002, 11:36 AM

Why do mustangs sometimes rev up and down at idle? The mustang I have now usually idles normal when I push in the clutch at a stop sign, but sometimes when I push in the clutch the rpms will drop almost to where the car dies. Then the rpms will shoot up real quick and then the idle starts going up and down. I hate being next to someone at a stop light and having my car doing that. I had an 88gt that did the same thing after I converted it to mass air. Does it have something to do with the cars' computer? Is there any way of fixing it?

05-11-2002, 11:36 AM	#1
bobtodd Registered Member Join Date: Dec 1998 Location: WI, U.S Posts: 255	Why? Why do mustangs sometimes rev up and down at idle? The mustang I have now usually idles normal when I push in the clutch at a stop sign, but sometimes when I push in the clutch the rpms will drop almost to where the car dies. Then the rpms will shoot up real quick and then the idle starts going up and down. I hate being next to someone at a stop light and having my car doing that. I had an 88gt that did the same thing after I converted it to mass air. Does it have something to do with the cars' computer? Is there any way of fixing it? __________________ 91 LX - 10.5:1 pistons, ported 289 heads, Ultradyne 588 cam, Cobra upper/lower, MSD, JBA long tube headers, Flowmaster, Richmond 4:10, roll cage, monster tach...FUN!! 95 SHO - K&N filter