As some may have seen in my post on "the welcome wagon" thread, I referenced some idle issues I've been having with my C head 98 Cobra.
The main problem I'm having is the rpms take their sweet time coming back down to idle after coming to a stop. I'll be driving down the road cruising at around 1800 rpm for example, and if I was to put the car in neutral while rolling the rpms will shoot up to 2000 rpm and stay there until I either put the car back in gear or come to a complete stop, and if I just simply let off the gas while in gear the car will accelerate until the rpms reach the 2000 mark. Even after coming to a stop, the rpms will sometimes continue to hang for up to a few minutes until finally coming back down.
So far I've discovered that the idle set screw has been tampered with by the previous owner. I purchased a new motorcraft IAC to see what changes, and discovered the car will not stay running unless given throttle. While I will have to go back and do it again to verify I did it correctly, I did do the idle relearn procedure with no new results. I've also had 2 separate well liked shops check for vacuum leaks, and nothing came up.
Anyone have insight as to what could be the issue? I'm confident the tampered with idle set screw is part of the problem, but I'm not sure if that is the only problem. One thing I will mention is I have yet to check the voltage on the TPS, I still need to get my hands on a voltmeter and check that off the list of potential causes. Thanks!!
The main problem I'm having is the rpms take their sweet time coming back down to idle after coming to a stop. I'll be driving down the road cruising at around 1800 rpm for example, and if I was to put the car in neutral while rolling the rpms will shoot up to 2000 rpm and stay there until I either put the car back in gear or come to a complete stop, and if I just simply let off the gas while in gear the car will accelerate until the rpms reach the 2000 mark. Even after coming to a stop, the rpms will sometimes continue to hang for up to a few minutes until finally coming back down.
So far I've discovered that the idle set screw has been tampered with by the previous owner. I purchased a new motorcraft IAC to see what changes, and discovered the car will not stay running unless given throttle. While I will have to go back and do it again to verify I did it correctly, I did do the idle relearn procedure with no new results. I've also had 2 separate well liked shops check for vacuum leaks, and nothing came up.
Anyone have insight as to what could be the issue? I'm confident the tampered with idle set screw is part of the problem, but I'm not sure if that is the only problem. One thing I will mention is I have yet to check the voltage on the TPS, I still need to get my hands on a voltmeter and check that off the list of potential causes. Thanks!!