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I am also having this same issue. Was it ever solved? I have cleaned my ICV and no luck.
Originally Posted by Kwpilot
Bringing this back since now I am having a surging idle issue about 30 seconds after starting the car. What we know as of now:
1. Car was idling fine prior to removal of UIM, TB and elbow for cleaning and gasket replacement. Which obviously makes me think this is self induced.
2. I tried to disengage the wax rod but am having no luck. The mount beneath the rod is able to be rotated is that normal?
3. I have replaced, cleaned and sanded down to bare metal the grounding points outlined in the service bulletin.
4. Temps are fine on the car and it runs normal but starts the surging idle when car is stopped.
5. I have not adjusted any screws or TPS yet.
6. Lower throttle cable seems a bit loose
Unfortunately I have not had time to do more troubleshooting. My next step is to test the idle air control valve to determine if it is faulty or not. If not I will attempt to adjust the air adjustment screw. Whenever I get back in town I will let you know the results. Did you recently change anything or did this start on it's own?
I've been down this road and solved it. Ignore any earlier post from me where I thought I'd fixed it but this was the final fix below:
If it was working before you took it apart, I'd take it apart again and check for a loose / damaged vacuum line and then put together and try again. Odds are much higher something popped off during reassembly than something like the idle air control valve broke. I had the same problem. Pulled the UIM for an auto to manual swap to get the auto trans off, then put it together and the idle was surging. Took the UIM off and one of the 3 vacuum source lines at the front of the UIM had popped off. Put it back together and it was still bad. Then swapped idle air control valve with another car even. Still bad. Then I found the vacuum line popped off at the MAP sensor during second reassembly - still bad. Out of frustration gave up for another month. Then I backed the car out and couldn't get it to start up again to park back in the garage. Figured the 16 month old gas was bad, so drained it and put it in my truck (which ran great on it) and then gave the FD new 93 octane. Voila - started up and idled perfectly. So I had two re-assembly vacuum line errors and gas went bad due to all the time it spent down. I love it that the FD wouldn't even start on it, but I put it in my truck and it drove just fine.
When it was idling up and down, I could unplug the idle air control valve (IACV) and it idled smoothly (of course idle dropped when turning on headlights or A/C since that's the purpose of the IACV). That made me think it was the idle air control valve and then I wasted a bunch of time trying to figure out what was wrong with the IACV even going so far as to swap it to no improvement. The real issue was just a vacuum leak plus eventually the gas went bad. Hope that's all that's wrong with yours too. Like 8 months later I got my other FD running with the original IACV and it idles fine too, so I know the IACV swap didn't help.
Is it possible to detect a vacuum leak with boost gauge? If so that's the first thing to do. When I get a chance this weekend I'll take one of my FDs and watch the boost gauge before and after introducing a vacuum leak and write up what you'd see. Then you know there's a leak or not rather than guessing if it's a leak or a bad IACV or a screw needing adjustment.
If it was running fine, you took off the UIM, then it idles poorly aft reassembly, I'd definitely take it apart again and inspect and replace any questionable vacuum lines, and put it together again before adjusting any screws. After all it was running fine before with the screw in the original position. The screw is just going to raise or lower idle, not make it hunt up and down and not fix an up and down hunting idle. Even my trusty local FD shop adjusted the idle screw and thought that fixed it, but it was really a vacuum leak.
Thanks for the response. I pulled off the UIM and found no leaks, loose grounding strap and it looked like my uim was not on tight enough. Fixed all those things and still had rough idle. Then I started to adjust throttle and cruise control cable while the car was running and noticed my cruise control cable was to tight. As soon as I loosened it the rough idle went away. Thanks!
I've been down this road and solved it. Ignore any earlier post from me where I thought I'd fixed it but this was the final fix below:
If it was working before you took it apart, I'd take it apart again and check for a loose / damaged vacuum line and then put together and try again. Odds are much higher something popped off during reassembly than something like the idle air control valve broke. I had the same problem. Pulled the UIM for an auto to manual swap to get the auto trans off, then put it together and the idle was surging. Took the UIM off and one of the 3 vacuum source lines at the front of the UIM had popped off. Put it back together and it was still bad. Then swapped idle air control valve with another car even. Still bad. Then I found the vacuum line popped off at the MAP sensor during second reassembly - still bad. Out of frustration gave up for another month. Then I backed the car out and couldn't get it to start up again to park back in the garage. Figured the 16 month old gas was bad, so drained it and put it in my truck (which ran great on it) and then gave the FD new 93 octane. Voila - started up and idled perfectly. So I had two re-assembly vacuum line errors and gas went bad due to all the time it spent down. I love it that the FD wouldn't even start on it, but I put it in my truck and it drove just fine.
When it was idling up and down, I could unplug the idle air control valve (IACV) and it idled smoothly (of course idle dropped when turning on headlights or A/C since that's the purpose of the IACV). That made me think it was the idle air control valve and then I wasted a bunch of time trying to figure out what was wrong with the IACV even going so far as to swap it to no improvement. The real issue was just a vacuum leak plus eventually the gas went bad. Hope that's all that's wrong with yours too. Like 8 months later I got my other FD running with the original IACV and it idles fine too, so I know the IACV swap didn't help.
Is it possible to detect a vacuum leak with boost gauge? If so that's the first thing to do. When I get a chance this weekend I'll take one of my FDs and watch the boost gauge before and after introducing a vacuum leak and write up what you'd see. Then you know there's a leak or not rather than guessing if it's a leak or a bad IACV or a screw needing adjustment.
If it was running fine, you took off the UIM, then it idles poorly aft reassembly, I'd definitely take it apart again and inspect and replace any questionable vacuum lines, and put it together again before adjusting any screws. After all it was running fine before with the screw in the original position. The screw is just going to raise or lower idle, not make it hunt up and down and not fix an up and down hunting idle. Even my trusty local FD shop adjusted the idle screw and thought that fixed it, but it was really a vacuum leak.
I will be able to check all the vacuum lines next weekend. I appreciate this post and it offers good advice. I pulled the trigger and bought some new vacuum line. Couldn’t hurt to replace the old stuff. Hopefully I will get this sorted out and report back my findings, thanks again.
Thanks for the response. I pulled off the UIM and found no leaks, loose grounding strap and it looked like my uim was not on tight enough. Fixed all those things and still had rough idle. Then I started to adjust throttle and cruise control cable while the car was running and noticed my cruise control cable was to tight. As soon as I loosened it the rough idle went away. Thanks!
interesting, was yours showing the same symptoms as mine in the video? How big of an adjustment did you have to make?
Going to drain my gas tomorrow and see if this solves the surging issue. I just got the issue today after getting it running, it was sitting for awhile so I can see bad gas as the likely culprit.
Going to drain my gas tomorrow and see if this solves the surging issue. I just got the issue today after getting it running, it was sitting for awhile so I can see bad gas as the likely culprit.
My ended up being a bad idle speed control valve. Ended up deleting it. Good luck.
