Idle air control valve problems help! 1996 volvo 850 NA

[Hunter96850na]

In the past couple of days my 1996 850 10 valve has been having a problem, where if i step on the gas while in neutral or park, the engine will stay at whatever rpm i rev it to until i turn the engine off or put it in drive or reverse. I thought maybe the tgrottle cable was sticking but it was not. I unplugged the IAC sensor, which seemed to help but it idles too high as if it is cold when parked or in neutral, but idles too low in gear. This leads me to believe that the valve must be getting stuck open due to gunk somehow? Or maybe a problem with the sensor? Any help is appreciated! I am going to clean the IAC tommorrow and see if it helps.

[erikv11]

Another potential part to look at here is the TPS but I'd definitely start with the IAC.

So nothing to add really except that cleaning the IAC is a good idea here. Let us know if that fixes it.

[misha]

Unplugging IAC valve should kill the engine instantly...unless throttle cable is binding and keeps the throttle opened.

If both mentioned are ok ...then you have a large vacuum leak somewhere in the intake.

[manovlov]

I would also check the camshaft sensor.

Camshaft sensor .jpg (118.9 KiB) Viewed 970 times