does anyone know what can cause the idle to oscillate? the oscillation is constant and consistent. if i play with the air bleed screw and take the idle to even higher rpms, the oscillations intensify. its strange cause each oscillation last around a second. so in a second the rpm will jump from 850 to 1000 and then back to 850.

 

Do you have the stock ecu still?

 

yeah i do? i am upgrading to a power fc in a couple months. will it go away with it?

 

You may have a minor vac leak, possibly in the LIM.

Besides flutuating idle, does it ever stall?

 

For some reason the ecu is trying to adjust the idle, hence the rythmic up and down. Check for a loose vacuum hose somwhere. Have you done any work recently where you may have knocked into one? Check the MAP sensor and the egr stuff. Also, check the airpump. It can screw with your idle.

 

yeah i noticed, one of the pumps is doing something strange.

i dont think its the LIM because i sprayed a carbeaurator cleaner around the LIM but the idle didnt go up at all. i checked the UIM using the same method aswell.

yeah, i replaced the vacuum hoses in the car. but i spent around 2 hours just making sure that the vacuum hoses put in were correct etc.

how do you go about checking the MAP sensor? and how do you check the air pump?

 

if the ecu is trying to adjust it, then could it be the tps? i just recalibrated the narrow and full range on the tps though.

 

THIS was my problem on my *sold* :-( 93 rex, the clutch was going out.

Does it only oscillate when you have the clutch depressed and are in gear?

 

yes rjuge: i have noticed that it is prominent when i put it in gear. but, i recently installed an ACT street/strip clutch and a new flywheel.

 

Mine does this between 1200-1000 rpm on COLD START-UP ONLY. It only lasts for less than a minute, and then the idle settles down to 750rpm constant. Any ideas?

BTW, stock ecu.

Thanks,
Jeff

94 VR PEP
M2 Downpipe
RB Catback
RB Intake Duct
Manual boost control
SR Radiator
Pettit AST

 

play with both idle screws and you should be able to get it to stop if you screw with it long enough. do that only after youve checked for vacuum leaks everywhere....

 

vac leak