Have an ST170. Upon slowing down, idle goes high and then drops, have done brakecleen test on gaskets & seals and also MAF cleaned with MAF cleaner as was quite dirty. Idle is now only rising to 1500rpm instead of 2000. Sometimes it still holds high idle, other times it drops normally. Could the MAF need replacing?
My car has a manual transmission.
This may be related to the idle air control which regulates the air flow into the throttle body as it is mixed with fuel prior to being injected into the motor. When this is not working properly, this will cause the motor to stall or idle erratically. I would recommend having an expert from Your Mechanic come to your home to diagnose and repair your idle air control valve.
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