2.5L ('98-'01) Rev hang

[Micahfriesen]

What all could be causing rev hang on my pickup? manual transmission, 2.5l. If I unplug the iac valve, it idles really low/stalls, but no rev hang. When I plug it back in it idles fine, but fairly bad rev hang. I know these engines have it to begin with, but it has gotten worse within the last little while.

 

[scotts90ranger]

The only thing I know of on these is the IAC is related to the VSS so if the sensor on the rear axle is iffy then the IAC could get goofy

 

[Micahfriesen]

If the sensor in the rear axle is iffy, wouldn't the speedometer be a little iffy as well? Because the speedometer works just fine.

 

[scotts90ranger]

Yes you are correct but the only things I've heard of causing that is sticky IAC, VSS or the one I just remembered is the power steering pressure sensor, if you have one it would be in the pressure hose leading from the pump to the rack.

 

[Micahfriesen]

Interesting. I managed to get air in the power steering system with the most recent work I did on it (turned the steering wheel with the engine off). The problem showed its face after said mechanic session. If that is indeed the issue I would have never connected the two.

 

[Micahfriesen]

So how would I go about determining if (a) the power steering pressure switch is bad, (b) my power steering system is low pressure (why?) (c) I have a different problem?

 

[scotts90ranger]

From my understanding the switch in the hose is looking for a high pressure in the hose (IE turning) and will increase the idle speed so you have more pressure available, mine doesn't seem to be working but my steering sucks so I'm not sure, was hoping someone else would chime in...

 

[Micahfriesen]

Well I tried unplugging the power steering pressure switch, and no change. The check engine light didn't come on, i kind of expected it to.

 

[Micahfriesen]

I finally got around to ordering a new delphi idle air control valve, no progress on the problem unfortunately, same symptoms as before.