I have a 93 si and on day it started surging while idleing. It pulses between 1500-35000 RPMs. I have checked the iacv, map, tps, valve timing, and all vacume lines. I am stumped!! The idle adjustment screw on the TB does nothing. The only way I can get any change is to retard the timing all the way and adjust the idle screw all the way in. Im sure the timing is straight. I love that it wont throw any codes so I have no idea what to do. Please help!! Oh yeah......Does anyone know what that sensor on the back of the intake manifold top right with the cap on the top does?? Thanks in advance!!

 

BUMP!! Please help!!

 

i have the same problem, no idea wut the problem is mechanic said i have a defective throttle but im not sure if thats gonna solve my problem

 

check your throttle body gasket

 

Take it to a shop and have them do a thorough run down, mine was some type of valve thing i had never heard of, like wax idle thing, i dont even know. Cant hurt.

 

fast idle air valve or it might be fast air idle valve