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View Full Version : Rough or intermittent idle?



yesitdoeshaveteeth
01/30/2011, 12:08 PM
Where do I start? haha - Well after buying my VX back in about April of last year and doing most of the basic maintenance that I could, considering I live in an apartment complex and not a house with a garage where I could concoct all sorts of mad science experiments (I.E. Mr. Fusion for the VX) - I've done all the basic stuff and up until a week ago the VX has been treating me to a wondering daily driving experience, minus a intermittent ABS light that I haven't seriously dived into fixing, although I very much want to.

So one day as I'm driving home, beating the usual NOVA rush hour traffic, about a couple miles from home my VX just shuts off....lights flashing like I pissed off NORAD, I coasted to the side of the road fighting the lack of power steering. Once I composed my thoughts, I put it in park and fired it up, it started completely fine. Of course now I'm in that fuzzy boggled/bewildered/panicked mode to just get the VX home so I can further troubleshoot this. At the next stop light is when I notice that when idling it would fluctuate between 1000 to nearly 0 RPMS. After forcing it to get home, I checked online to consort with my fellow VX'ers as to what the hell was my VX doing. The consensus that I got was that it was most likely my TPS sensor or my IAC valve.

So of course, leaving nothing to chance, I bought both parts along with the customary PCV valve and a can of Sea Foam and throttle body cleaner. As I thought, when I replaced the IAC valve, it was caked with carbon - removed the old gasket, fired a little throttle body cleaner in the hole and wiped what I could. The TP sensor was pretty straight forward, a little muck in its spot but nothing crazy, I used a few Q-Tips with some cleaner to clean that area out. Now, it should be noted that with my new IAC valve, it come with a little pamphlet that mentioned to set the IAC before installing it, basically by pushing it in so that it didnt stick out more than 1-1/8" than where the gasket sits. It also mentioned that after installing it, in order reset the IAC, I would have to drive upwards of 40MPH so that the ECU would send a signal to the IAC to reset its position.

As soon as I started it though, it immediately went to about 2000RPM - I feathered the gas pedal to sort of see what it would do and it lowered a bit. Deciding the hell with it, I stuck it in drive and went for a little cruise. Not more than 100ft down the road, it died at its first stop sign...."Damn you misleading forums..." I thought to myself. Started it up again and zipped around my block to find a place to get to 40MPH to test what the pamphlet said. Now after driving around for about 20mins, I noticed it wasn't really doing the fluctuating idle RPM thing, as much. After getting home and having it in park, it was fine - but as soon as I rev'ed it up, it would flutter when it got down to the less than 1K range....but not always.

So, in short, after replacing the parts and doing the "reset" - the abnormally high RPM issue hasn't popped up again, and the idle rpm issue is now not nearly as prevalent but its still there.....

Any help or suggestions concerning this issue would be greatly appreciated!!:bwgy:

VXR
01/30/2011, 12:32 PM
intake manifold gasket?

yesitdoeshaveteeth
01/30/2011, 01:11 PM
I saw that as a solution on here, but my only question to that is, just all of a sudden? There was really very little warning about this issue. The only indicator I had was after thinking about it, when I started it up before leaving work it did seem to start a little low on the RPM side than I was used to seeing but other than until it acted up I didn't notice anything.

Would you happen to know how much a pain it would be to pop off the intake?

BTW - I miss the northwest, I grew up in East WA :)

VXR
01/30/2011, 01:56 PM
Would you happen to know how much a pain it would be to pop off the intake?

I had mine replaced at the dealership but I know there are many others here who can answer that:yesb:

Junster
02/13/2011, 08:36 PM
You might carefully with the car running do some small puffs of starting fluid here and there around the intake and esp the vacuum hoses. If the motor suddenly revs up a bit you've found a vacuum leak. A bad vacuum hose can be hard to spot. Also check the battery terminals. If they are tight maybe remove and clean the posts. Esp check if the originals are gone and somebody put a bolt on terminal on the battery wire