Trying engine

[reconrangerll]

I have a 2.3L 5 speed tranny. The rpm never drops whenever I have my climate control on the defrost setting. When I shift the transmission, the rpms never drop. Any suggestions?

[tomboy]

Do the rpm's go up when you hit the throttle?

[reconrangerll]

The rpms will increase with the throttle but when I shift the transmission the rpms won't drop.

[tomw0]

Defrost engages the A/C to dehumidify the air fed to the inside of the windshield. If the IAC was sticking, it might keep the rpms up too much. If this is for a 97 vintage, you should be able to use an OBD-II scan tool to read what the IAC is being ordered to do, rpm-wise, by the computer. You'd know if it was obeying the command or going off on its own(sticking?).
tom

[reconrangerll]

I have an obd-ll scan tool. I will see if I have a code on it.

[dvrich]

Another possibility is that if the a/c clutch is not engaging the engine might run up about 2000 rpm to compensate for a load that isn't there. That happened to me once so it's a possibility since the a/c runs in defrost, defrost/floor, and a/c.

[Woodtroll]

It could also be a vacuum leak in your climate control circuit. It will be harder to do with the engine revved up, but turn your selector to defrost and see if you hear a "hissing" vacuum leak anywhere under the dash or hood with the engine running. Of course, a visual inspection might reveal a line loose too. On any fuel-injected vehicle that won't idle, a likely suspect is a vacuum leak.

Good luck!
Regan

[rno5]

Mine does the same thing it will stay reved up till you feather the clutch to start rolling then it idelas down push the clutch in and it’s way up agin


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[99Ranger376]

Possibly the throttle position sensor, I had a ‘98 2wd 2.5L 5MOD that did the same thing and it fixed this problem, also look for vacuum leaks.


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[Muroki2.3]

I have to ask, does the defrost/climate control work?


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[tomw0]

The defrost setting is the last one that needs vacuum. As a matter of fact, it doesn't need any vacuum to go into defrost. Defrost is the default setting if vacuum is lost, so that you will be able to see out the windshield in case of freezing or condensation.
You can pretty much get by with the A/C blowing in the wrong place, but if you want to be able to see, you'd better have defrost available, so it is set as the 'default' position of the mode selection 'door' as a fail-safe.
If the TPS -throttle position sensor - were to fail, the computer might think that you had your foot on the gas pedal when you did not. It would then 'prime' the IAC to be ready to go into action when the speed sensor indicated you had come to a stop. It, the computer, also uses the IAC to compensate for the loads of the A/C compressor and power steering pump when the engine is at low rpms, in addition to its cold fast idle function when the engine is first started. If your idle sticks when you start from cold with a high idle, you may want to clean the IAC. The TPS can also have 'dropout' where the sweep is worn and the voltage goes to zero. That will fool the computer into kicking the IAC into gear when you are rolling down the highway. Complex, no?
tom

[btspencer]

Ok so my 3.0 did this a while back, Clean your MAPS, and IACM, those were the culprit in my case. I also found a couple vaccum leaks when it happened... So all in all it was a win. If this dosent solve anything, remove the plug on the back of your compressor, if this makes the issue go away, you can narrow it into that curcut.

[Isaacc44]

I had the same issue with my 97. Sometimes the rpms would stay high at a stop and sometimes my truck would bog. Then finally i broke down in traffic on the highway. I pushed it to the paint store then had someone take me to autozone to get an IAC. Slapped it on and it ran great

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