I have had this problem for over a year now and so far nobody has been able to figure that out. With that said, this problem doesn't seem to prevent me from driving, it has never stalled or anything, so it's something I've just been living with. I would like to get it fixed though.
Here is what is going on:
When starting my car from cold, engine usually idles at 1000 RPM and will lower down to 650 which is normal, great. Only very recently has the engine started from cold and the idle didn't go up to 1000 which I thought was strange.
Around 50% of time when I place my car into park, the idle will get stuck at 500 RPM intstead of rising to 650 like it's supposed to. Or sometimes it will go to 650 rpm for a while and then I'll see it drop down to 500. I observed this frequently because with my short drive to work, I'd arrive just as my temp hit 80C, so I'd let it idle and get more fully warmed up before shutting it off. Sometimes it will surge between 500 and 650 RPM. Whenever the idle drops the engine usually begins to run poorly and misfire quite a bit. The rest of the time it will go to 650 RPM rock steady like it should and idles great.
Could one possible cause for this be an improperly installed throttle body? I don't recall this ever being a problem until I had my throttle body messed with a couple times at two different shops. The fact that the car was returned to me idling as high as 1600 RPM when at operating temperature says a lot (turns out the throttle return spring was not re-attached.) I would love to hear any suggestions. I'm dropping it off with my mechanic tomorrow so maybe I can help point him in the right direction with advice from here.
Side note: Engine seems to run best when COLD, as in smooth and no misfires. Only when the engine is at temperature I notice the engine will often have a slight misfire at red lights.
Here is what is going on:
When starting my car from cold, engine usually idles at 1000 RPM and will lower down to 650 which is normal, great. Only very recently has the engine started from cold and the idle didn't go up to 1000 which I thought was strange.
Around 50% of time when I place my car into park, the idle will get stuck at 500 RPM intstead of rising to 650 like it's supposed to. Or sometimes it will go to 650 rpm for a while and then I'll see it drop down to 500. I observed this frequently because with my short drive to work, I'd arrive just as my temp hit 80C, so I'd let it idle and get more fully warmed up before shutting it off. Sometimes it will surge between 500 and 650 RPM. Whenever the idle drops the engine usually begins to run poorly and misfire quite a bit. The rest of the time it will go to 650 RPM rock steady like it should and idles great.
Could one possible cause for this be an improperly installed throttle body? I don't recall this ever being a problem until I had my throttle body messed with a couple times at two different shops. The fact that the car was returned to me idling as high as 1600 RPM when at operating temperature says a lot (turns out the throttle return spring was not re-attached.) I would love to hear any suggestions. I'm dropping it off with my mechanic tomorrow so maybe I can help point him in the right direction with advice from here.
Side note: Engine seems to run best when COLD, as in smooth and no misfires. Only when the engine is at temperature I notice the engine will often have a slight misfire at red lights.
