low RPMS

[mercab18]

I recently went offroading with a buddy and the check engine light went on. After getting code 24 (Throttle position sensor input above the maximum (or below the minimum) acceptable voltage; or TPS signal does not correlate to MAP sensor) and changing the TPS, the check engine light turned off.

It drives fine, but when I stop with it in gear (drive, reverse, 2, or 1), the RPMs are extremely low, probably about 500. You can see it dropping until it hits probably 200 RPMs and then it jumps back up to 500. If I put it back into neutral or park, it goes back to its usual 1000 RPMs, but it chugs while I'm in gear. It even stalled on me once while I was stopped at a light.

Any help is greatly appreciated. Thank you.

 

[Bounty__Hunter]

1000rpm is a little high for idle.

Tell us some about your jeep. Model, year, engine, etc.

 

[mercab18]

I have a 97 Wrangler Sport with an inline 6 4.0 Liter engine. It has about 75k miles on it. Thanks again for everyone's help.

 

[Bounty__Hunter]

Does your speedo work? Correctly?

Which transmission do you have?

 

[mercab18]

I'm not sure what you mean by "speedo" but if it's the speedometer, then yes it works properly. The transmission is the stock one. I really seem to have any problems shifting, accelerating, or driving. It's just when I'm stopped while I'm in gear.

 

[jeepjoesXJ98]

how long have you had the problem? if its been just a few days you may have gotten some stuff wet let it dry out by unplugging some of the sencors like the map sencor and throttle sencor by useing a blow dryer on low...dont over do it, or it could be a small adjustment somewhere on the carb or fuel rail,intake system... but 1000 rpm is high for that, i got a 4.0liter in my xj with computer work and it idels around 650 to 700

 

[Bounty__Hunter]

I would remove your throttle body and clean it thoroughly, removing all sensors before using any solvent. Clean the IAC housing and IAC plunger and you should improve idling.

 

[mercab18]

I'm a little new to this, so could someone elaborate on how to clean my throttle body, the IAC housing, and IAC plunger? Also, what solvent should be used?

 

[Bounty__Hunter]

Remove the airtube to the throttle body, disconnect the throttle linkage, and disconnect the wiring to the 3 sensors on the throttle body. Remove the 4 bolts holding the throttle body to the manifold.

Remove all the sensors from the throttle body. The IAC housing, attached with 4 tamper-proof torx bolts, requires a special socket. You can use the same tamper-proof torx bit on all the sensors. Once sensors are removed, you can clean the TB and IAC housing with a toothbrush and carb cleaner. Only clean the tip of the IAC plunger, you'll know what it is when you get in there, pretty simple stuff.

 

[mercab18]

I just followed the instructions given by Bounty Hunter (removed throttle body, cleaned everything out, etc) and now the thing RUNS PERFECTLY!

Thanks for everyone's help in this

 

[Bounty__Hunter]

Glad it worked out for you.