weird rpms when car is in gear

[koreanmx-er]

so when im sitting there idling my car normally idles at around 600rpms just fine no half stalling or rough running engine, then when i put my car in gear , or any gear for that matter my revs go to 1500 and then drop and then go up to 1500 and then drop continually, and this is only when the car is warmed up and at a good idle to begin with , im confused , i thought the obvious , duh vacuum leak , well non there, but if there was a vacuum leak then it would be constant even if i wasnt in gear right? and it happens when the rpms go up when your in gear the ecu automatically adds rpms so its easier to take off without stalling, but im totally lost here any real help is greatly appreciated, and this problem has just been happening in say the last 2months thx ahead of time for help guys

<small>[ October 23, 2004, 11:10 PM: Message edited by: koreanmx-er ]</small>

[Zetgohan]

is your MAF plugged in all the way?

try using an electric contact cleaner on it to make sure its a good connection.

<small>[ October 23, 2004, 11:27 PM: Message edited by: Zetgohan ]</small>

[ZEmadman]

mine does the same thing...well, did. i havent changed anything on the car. make sure your connectors around your airbox and throttlebody are all secure.

[IanL]

Originally posted by koreanmx-er:
so when im sitting there idling my car normally idles at around 600rpms just fine no half stalling or rough running engine, then when i put my car in gear , or any gear for that matter my revs go to 1500 and then drop and then go up to 1500 and then drop continually, and this is only when the car is warmed up and at a good idle to begin with , im confused , i thought the obvious , duh vacuum leak , well non there, but if there was a vacuum leak then it would be constant even if i wasnt in gear right? ...

Not necessarily. When the rpms rise, the engine rocks over on its mounts due to torque reaction. That can flex the rubber piping (particularly the one between the VAF and the TB) and open up a small crack.

[koreanmx-er]

the crack in the tube when engine rocks seems like a good point but i have an aftermarket cai so no rubber tubing , umm im gonna try the cleaning out the vaf connections

[DavidOS]

if you reset your ecu and if the car is still learning then you also might want to set the car into diagnostic mode by jumping pin 2 and 10 i think they are.... i think.

Then set the idle when the cars hits idle temp.

Also check the IDLE screw, if its all the down and closed it can cause that rpm up down problem.

[papa roached]

its pin 10 and a ground

[koreanmx-er]

well cleaning out the vaf connections did jack squat , i'll try resetting ecu tommorow

[Grants]

It made sure they weren't dirty and proved that wasn't the fault though....

[koreanmx-er]

im still lost here guys!! any help?

[papa roached]

you adjust your TPS?