rpm too high

2000 JEEP WRANGLER
108,000 MILES • 4 CYL • 4WD • AUTOMATIC
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JASONMCC
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  • 3 POSTS
my 2000 wrangler is running 3200 rpm at 68-70 mph what would cause this..
Feb 13, 2011 at 3:43 AM
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RASMATAZ
  • ASE Certified Mechanic
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  • ASE Certified Mechanic
High Idle:

USUAL CAUSE
The usual cause of abnormally high idle speeds are vacuum leaks or an inoperative idle speed control motor. A vacuum leak on a fuel injected engine will cause high idle. The oxygen sensor will detect the extra oxygen that is entering the engine through the vacuum leak and will signal the computer the exhaust is lean. The computer in turn will then provide additional fuel which will result in an abnormally high idle.

DIAGNOSIS
The first step in the diagnosis is visual inspection. Inspect the throttle cable and linkage for binding. Inspect the engine for vacuum leaks. With the engine at idle, visually inspect each vacuum hose on the vehicle. Listen for a hissing sound which is a key indicator of a vacuum leak. Repair the vacuum hoses as necessary. Inspect the PCV valve and hose. Using pliers, pinch off the hose that supplies the PCV valve. The engine speed should drop slightly. If the engine returns to a normal idle speed, the PCV valve should be replaced. Consult a vehicle specific service manual for location and specific testing procedures. If the vehicle is free from vacuum leaks and the PCV valve is functioning normally, the idle speed control motor or valve may be defective.

Feb 13, 2011 at 3:46 AM
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JASONMCC
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No i may not have explained the problem properly.. It,s like the jeep is not shifting into overdrive..and is the 2000 jeep wrangler automatic transmision a 4 or 3 speed?
Feb 13, 2011 at 7:37 PM
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