93 f350 idle control valve issue

[khartz]

I have a 93 F350 and the idle was really high and I was told it was most likley the ICV. I took it appart and cleaned it out but when I put it back in the same issue was still happening. when I disconnected the ICV wiring from the unit it ran fine but a bit lower in idle. All was fine but I noticed that the shifting of the gears was not the same. I can deal with that issue more than the super high idle but I was wondering if there was a sensor that would effect the two since it seem that the valve is ok but somthing controling it was not.

Any advice you might have would be much appreciated


Thanks

 

[blacksnapon]

A vacuum leak will do the same thing. I suggest using carb spray or brakecleen spraying it on all areas that could be leaking. When the engine speed changes, you have your leak.

 

[khartz]

I tried that already and there was no change. I also checked the PCV valve since I heard that can cause it as well. When I disconnect the plug on the Idle control Sensor the idle drops to more normal. I am not sure the problem is the valve but more the components like the AC that send a signal to the sensor. I believe the transmission and the AC send a signal to the sensor to raise the idle slightly. thanks

 

[blacksnapon]

All the IAC motor does is control the air flow (kind of a controlled vacuum leak, like egr) to change engine speed. If you are getting the proper amount of air flow, the engine will die if the IAC is unplugged. If too much air is available, the engine will not die. Severe vacuum leaks will cause driveability issues. Small leaks will show only under certain conditions. Different tests can simulate these conditions. Spraying carb cleaner, blocking the throttle body flow, pinching off lines, etc. Try to limit excess air flow (blocking throttle body) while unplugging the IAC.

 

[d-kuzmen]

I had a f150 that did this same thing I ended up changing the mass air flow sensor not sure if your 93 has one but if it does maybe worth a try. Also make sure your throttle plates are not sticking.