OK here's the deal: My 2002 XG350 just started freakin' out on me tonight: Engine is at normal temp, it's 25 degrees Celcius outside, and the engine is idleing at 3000 rpm??? I went for a 15 min. ride to see if it would calm down and the answer is: NO! Still 3000 at red lights, stop signs and back in the driveway... Actually this is quite dangerous 'cause I need to brake quite in advance to get to a complete stop. Usually the engine runs at around 600-700 rpm when on drive or reverse but now it's 1200-1300. Also causes the tranny to "jump" into drive or reverse when I select those 2 positions... There ya go! Guess I've been clear 'bout the problem! Hope somone can help! Thanks in advance!

 

It's really bad for your transmission to run that way too.

It's probably an intake leak. You can track it down by getting a spray bottle of water, and spray around the intake until it starts to slow down.

If it's not an intake leak, it could be the idle control valve went bad. You can test that by removing the valve and plugging up the openings.

 

I'll try that thanks! I thought it could have been a computer problem so I unplugged the battery for 5 min. and plugged it back but it did not changed a thing. So guess I'll be checking for leaks!!

 

Checked this mourning: No intake leak! Coud it be a sensor??? Like the throttle positioning sensor?

 

Chect the IAC (Idle Air Control) valve on the throttle body.

 

Listen to that: After looking for leaks yesturday mourning and finding nothing I started the car in the afternoon just to see if it repaired itself... IT DID!! Now how the heck can that be?? No more 3000 rpm on idle? If there is Hyundai techs around here I've got a question: Does XG's have minds of their own?!

 

The IAC was stuck, and it unstuck itself. The problem will probably return.

 

I have change 3 sensors and my problem persists.please help😞

 

This is a 10 years old zombie thread. Please start a new thread and describe your problem with your own words. It will help if you give us the trouble codes and if you tell us which sensors you replaced. It appears you fell into the trap of throwing parts at an improperly diagnosed problem.Don't answer here. Start a new thread.