rpm going down @ 2000 to 1500
 

hello i have a problem with my supra mk3 when the rpm goes up to 2000 fast falls down to 1500 and if i keep the accelerator in same position rpms in my car keeps going up and down from 2000 to 1500 what is wrong????

is your car turbo or n/a?

its a turbo supra 89

could be a boost leak. if not that, check TPS and AFM. if not them, check IAC.