Start Up Idle Seems High

Garry Moss · Feb 2, 2018

hey Peeps

My 04 ST has been idleing up around 2500 during start up, during cold and warm. Seems to take awhile for it to come down. I did replace the IAC a few weeks ago but this just started yesterday. Any ideas?

swshawaii · Feb 2, 2018

Normal for mine too, although only up to about 2k, then settles down to about 700 revs within 5 seconds. Probably wouldn't hurt to clean the throttle body and spray the MAF sensor filaments with the specific CRC cleaners if you haven't done it yet. GL

Garry Moss · Feb 2, 2018

Its seems to stay at 2500 rpm for awhile. I just had it smogged, would they have disconnected anything that maybe they didnt put back?

swshawaii · Feb 2, 2018

Only thing I can think of is the breather tube connected to the intake hose by the MAF and air box. I'd scan for stored trouble codes in memory regardless whether you have a check engine light or not. High idle started right after emissions check? Mine threw a CEL with a "P0507 Idle Control System RPM Higher Than Expected" code ONE time, but I cleared it, and never happened again.

EddieS'04 · Feb 3, 2018

If you dont find an intake leak. Try when motor is cold. Disconnect the neg batt cable for 10 minutes. Then start it and let it idle until the idle is normal, before driving it.