Engine idle higher than usual

[redwrangler02]

Recently my tj has been idling higher than usual (usual being 500-700rpm) and for about the last couple weeks or so its been idling at close to 1500rpm. My jeep isn't throwing any codes. About a year ago I had a similar problem but I had a code and it turned out to be the throttle positioning sensor. Any ideas about what might be the problem or how I would go about figuring out whats wrong without codes? Maybe o2 sensor going out? Thanks guys

2002 Jeep TJ, I6, 5 spd standard, 104k miles

 

[William1982CJ7]

Some TPS sensors have a slight adjustment to them. I would check that out

 

[SteelHeadz]

High idle is often a vacuum leak issue. If the vacuum leak is large enough, the PCM will command the fuel injectors to stay open longer thus end up in a high idle situation. check the intake gasket, vacuum ports and throttle body gasket for a vacuum leak. The second thing that comes into mind is the MAP(Manifold absolute pressure) sensor. A stuck pressure sensor will give the PCM a false reading. Third, the IAC motor. If the pintle gets stuck half way open all the time then the idle will stay up in the higher rpms. Possibly dirty due to carbon build up.

 

[William1982CJ7]

Good advice Steel

 

[Mark 47 willys]

Does the throttle body have the fine wire sensor to measure air temp. If so their is a spray cleaner at auto stores to clean it. I cleaned my air filter (K&N) and put too much oil on it and coated the wire.

 

[Bounty__Hunter]

Does the throttle body have the fine wire sensor to measure air temp.

No it does not.

A tip to find a vacuum leak is to use an unlit LP bottle, the small type used by plumbers to sweat copper pipe. Turn the valve on and run the gas (no flame) around the throttle body and intake manifold. The idle will go up if you come across the vacuum leak.

 

[jfrabat]

X3 on the vacuum leak, especially since the idle went up when no mods where made...