I just had new spark plugs among other things at my last service. Now the car wants to jump between about 500 and 800RPM at idle. Also, when the car is around 1000 to 1500RPM I feel the same kind of hesitation or surge. I did a search and came up with "take it to the dealer". I want to avoid that at all costs. Any ideas?

The car was taken in for service and returned in worse shape?

Take it back! Tell them to fix it!


What else was done? Is the check engine light on?

How many miles do you have? Could be your CPS's or O2 sensors.

I have 138K. No check engine light. They replaced a valve cover gasket, alternator, and charged me dearly for it. Before I took it in, it would hesitate for about the first 2 or 3 minutes I was in the car. Now, it does it all of the time.

I just had new spark plugs among other things at my last service. Now the car wants to jump between about 500 and 800RPM at idle. Also, when the car is around 1000 to 1500RPM I feel the same kind of hesitation or surge. I did a search and came up with "take it to the dealer". I want to avoid that at all costs. Any ideas?

I have seen many threads about the subject of rough idle and hesitation, but I rarely see any solutions. I did, however, have a hesitation on deceleration. It turned out to be a vacuum leak that I found.

I still have hesitation when cold (accelerating) and I have a miss when idling, but BMW and two indy shops could not find a problem. They did extensive testing including a smoke test and found nothing. Other than swapping out parts and waiting for a CEL, I have given up.

I think computer geeks need to be in the diagnostics arena and get rid of the parts swappers. We could find these gremlins if we could get into the brains of these cars. Maybe lower the threshold for throwing a code. Not sure what to do about the guys working on troubleshooting these cars, but they do not impress me.

I have the same issue as 540-S3, and I'm waiting for my code. The problem for me is this: I could dive into all the possibilities, repair it all, and HOPEFULLY get it solved. I cleaned my ICV and my MAF, and it did indeed get better.

I will do a little cleaning and see what happens. Thanks for the tips. This site rocks.

If it's an intake manifold gasket leak, it will eventually do this:

http://img.photobucket.com/albums/v622/cocainsahellofadrug/Hollis%20E39%20540iA/th_DSCN2689.jpg (http://smg.photobucket.com/albums/v622/cocainsahellofadrug/Hollis%20E39%20540iA/?action=view&current=DSCN2689.flv)

I'm in process of fixing mine up. Mine had the exact same symptoms you described and I know exactly the "surge" feeling you mentioned too. Mine wasn't that noticeable in the begining, but eventually worsened and once the weather turned cold it wasn't even drivable.

what's the update now after you clean your ICV??? does it happen more when you have the A/C on?

cheers,

richie

I cleaned the ICV and it worked wonders. I now have a smooth idle and it doesn't hesitate anymore, not even after a cold start up. A $4.18 and 15 min fix. This site has saved me sooo much money.

I cleaned the ICV and it worked wonders. I now have a smooth idle and it doesn't hesitate anymore, not even after a cold start up. A $4.18 and 15 min fix. This site has saved me sooo much money.
I cleaned mine too, but no help. Maybe it needs to be replaced. Any one know how to test ICV?

I had a weird issue with a rough idle and it turned out to be a blown CCV.

Any smoke at startup? Rough idle?

Look into the intake manifold and see if there is any oil in there. I also had a crack in some tubing that is b/t the CCV and oil seperator which was pulling in some air and pushing the RPM's up.

I'm not sure if this even helps, but who knows...

I cleaned mine too, but no help. Maybe it needs to be replaced. Any one know how to test ICV?

From what I was told in my thread, If you unplug the ICV and there is no change, the the ICV is indeed bad. :(