What is proper idle speed for a '92 4.0L manual tranny Expolorer?

[jwv3]

I've been trying to figure out why my truck is idling at 1000 rpm's. I've searched the site and only found one or two posts that say it should be 650-750 rpm's. Is this correct for manual, 5-speed Ex's?

It isn't a rough or erratic idle, it is smooth and accelerates fine and settles back down to 1K all the time.

Here is what I have done so far:
New Idle air control installed today.
MAF sensor cleaned. (twice)
TPS set to 0.965 volts at closed throttle position (and verified 5 volts power side).
Checked all vacuum hoses one by one and by removing each and plugging the port. no leaks found.
Sprayed carb cleaner around base of intake manifold to check for leaks, none found.
Verified that the throttle butterfly is closing completely.

Any suggestions would be appreciated.

 

[jd4242]

Maybe new fuel filter and check fuel pressure

 

[jwv3]

The fuel filter was changed when I did an engine swap. I've put about 800 miles on it since then. It doesn't stall, sputter, miss or seem sluggish one bit, (some other things I would expect from a clogged filter).

I do need to get myself a fuel pressure gauge, though.

 

[jd4242]

Yea when my fpr when out it idle high like like but ran fine.did you clear the computer after you replaced and cleaned evrything?

 

[jwv3]

I disconnected the battery this morning after I set the TPS voltage to 0.96 and cleaned the MAF sensor while it was disconnected. That was about a half an hour. Is that long enough to clear the computer?

 

[jd4242]

Should be,I left mine off overnight.high idle seems to be hard to track down on our motors.maybe the ball is stuck in the breather on the driver side valve cover,easy thing to check

 

[jwv3]

Should be,I left mine off overnight.high idle seems to be hard to track down on our motors.maybe the ball is stuck in the breather on the driver side valve cover,easy thing to check

Are you talking about the PCV valve? If so, that is new also and I can hear it open and close when I pinch the hose while it's idling so it seems to be working.

 

[Reejerey]

having just put a motor in it, I'm going with vacuum leak. check and make sure all the ports on the vacuum tree on the manifold are plugged off or have hoses connected to them. Also make sure that those hoses are connected to something and not broken anywhere along their length. Just spraying carb cleaner doesn't always work, as the carb cleaner actually has to hit the vacuum leak pretty directly to get a result.

1/2 an hour is long enough to clear the codes and adaptive learning in the computer btw