Could a bad throttle postion sensor cause the motor to idle from 500 rpms to 1200 rpms and back to 500 and so forth? i have checked for vacc. leaks and found nothing..... i have a VAFC-2 ( i know gay, gunna get chipped ecu soon ) and when the car starts to flucuate in idle if i get the rpms up a little then it stops like if i hold it at 2000rpms but if i watch the vafc-2 its says the rpms are at 2000 but if i countinue to hold it there at say 2% throttle at 2000 rpms the 2% throttle will stay the same but the rpms will drop slowly tell it gets back down to 500 rpms and begins to idle from 500 to 1200 (back and forth) then if i let off the throttle it will kill the motor?? dose that mean TPS is bad? any help thanks

 

Did you recently put in a new motor or change any plugs around? They might be mixed up.

 

Its a D16z6 and the problem started before i went to turbo setup ... the motor was basically stock like header MSD with external coil And it happend right after i put on a new clutch and lightend flywheel ( 8.5lbs )

 

With the motor running pull the charge pipe so you can see the inner bore of the throttle body. With the motor at operating temp, put your finger over that lower left hole inside the tb. If that is pulling vacuum with the motor warm, then the thermo valve beneath the tb is the problem. It's hanging opened because the seat is probably unscrewed.

 

ok just did that and it is pulling vacc. pretty good suck too can leave a hicky.... how do i fix this????

 

bump

 

ok got it cleaned out and screw all the way in and idle problem GONE!!!!! yeah thanks for the help! so happy

 

i dont have the thermo valve beneath the tb