lately i have been noticing my car idling very high then dropping off, then up and down... its very weird, sometimes it will be at about 1000rpm, then while just sitting in neutral it will rev to close to 2000rpm. there is no rhyme or reason to when it happens, sometimes its just at startup, sometimes at stop signs, even while i'm driving, i can be cruzing with it around 1500rpm but when i clutch it will go up to almost 2000rpm until i go back into gear
any help would be great i really have no idea what is going on, its been a while since this has happened, but its getting alot worse.
~Jeff
Try this. With the car idling high, disconnect your TPS sensor. Your idle should drop. Reconnect the sensor. Your idle should stay low or lower than it was. Shut the car off. Disconnect the battery and let the car sit a while. If possible until it's completely cold. Reconnect your battery and start it up. It may idle higher than normal, but still should not be up around 2000 like it was.
My 2001 did that for a while until I found a post on another forum on how to do this. It has fixed several others on this board who have tried it.
Forgot to add. After you reconnect the battery and start it up, the idle should drop as the computer relearns everything.
mine did that with a vaccum leak... but try ^^^^^^first
8 psi with m62 and IAT under 100
it sounds like you had the same thing i had... not sure if you have the same tb assem as me.. but somehow the connecting rod between the tb actuator(where the cable is connected and where the 'stop' screw is) and the actual butterfly is 'bent'... you can test this theory by first doign as mentioned above w the tps.. then take off the air inlet tube to the tb.. put your finger over the IAC inlet.. if it does not shut off you either have the bent tb rod, or a vacuum leak
the pcm will not throw a code for the bent conecting rod because the TPS sensor (at least on my 02 z24) is to the right(looking towards the driver from the front of the car) side of the butterfly, the actuator cable and etc is all onthe left.. if you pull the pcm data stream it will show that the computer thinks you are actually holding the throttle down a little bit it will show 1-5% throttle.. now there is usually a little lea way at ~5% but if the pcm sees there is decreased vacuum shown by the MAP sensor it will think you are actually on the throttle
as for the continuous revving up .. usually when you engage the clutch while moving >10mph.. the IAC valve is set to open a certian amount of 'counts' when you are moving.. in case either the ABS kicks in, continuous usage of the brakes(brakebooster needs vacuum), usage of power steering and/or a/c engagement..all possibly when in combination causing a stall at normal idle. which is not what you want. so it will , when everything is perfect. idle around 1250 at >25mph when in neutral or clutch engagement... and goes down by some type of percentage to normal idle as you slow down
check out my previous threads
people have sold their cars due to this problem... if you want to sell it to me,
-thomas
the butterfly is not bent,b ut the rod is bent... clarification
What is the mileage on your car? This seems to be an ongoing problem. I have the same problem with 140,000 miles.
