1995 EX 4.0L OHV. My idle speed in neutral has crept up > 1,100 to 1,200 RPM. With the IAC valve disconnected it slows down but not quite back to normal. Changed IAC valve.... same problem. Checked engine and air temp sensors with ohmeter back to the PCM connector and they're both within spec cold & hot. TPS sensor seems OK running at 1.1 VDC at idle. All visible vacuum lines are in good shape and connected. I tried another PCM unit
(used) and it has exactly the same symptoms. I'm getting close to a trip to the dealer but cringe at the idea.
Any help would be appreciated !!
DWB

 

Try getting the TPS lower at idle, like under 1.0
vdc...

 

Did u try the mass airflow sensor my truck the onnector fell of and it did that and my check engine light came on ur light maybe off but the mas might be going out

 

I finally fixed the problem.
It was a vacuum leak in the upper intake, around the
end of the metal tube which leads to the EGR valve, right where it enters the plastic intake.
Used some silicone to seal it up.
Idle speed now back to normal.