yuyo

I have a 96 ls that i have not drivin for about a year and for some reason when i came back home and started it the idle goes up and down can some one please help me thanks.....

CitySlaka

I had the same problem about a year ago. I could only drive for an hour before it started acting up. The problem ended up being the belt tensioner assembly, which by the way is a dealer specific part that will run you 400 bucks. There is a really good tutorial site I use when replacing anything to do with the ls400 called lexls.com check it out, if you have alittle knowledge about cars you can do the repair yourself its not to hard just get the torque specs. Hope this helped.

steve2006

If it's been stood that long check all the rubber vacuum hoses for perishing or splits or if left outside even rodent damage!
If all looks OK clean the IACV and the throttle body.
Did you put fresh gas in the tank?

hobojoe

Also, could possible be the TPS (Throttle Position Sensor) happened on mine before.

yuyo

thanks for the responds cant wait for the sun to come up to get on it no i haven't put any new gas, today i changed the spark plugs and wires hoping that was it but no difference...

yuyo

finally got a break from the rain went out cleaned the throttle body changed the gasket drained the radiator and replaced the thermostat i used the pink coolant. i also changed the spark plug and spark plug wires and the idle still going up and down. can some one please help asap i need the car before this sunday...

andyman32

Throttle position sensor would be the first thing I'd look at. Exact same symptom happened on one of my former Jaguars and a neighbor's Jeep.

yuyo

so i pulled the erg and look what it looks like..






do you guys think this might be the problem... and if so is it possible to fix or repair with out replacing it if possible i don't want to spend the $700....

dvourthis

might be the problem, clean it well and reinstall. I just had to replace my ICV (idle control valve). It was doing the same thing as yours, it would rev up, drop down, die, restart, die, restart, rev up, etc... the ICV controls the idle which is what yours sounds like it isnt doing. cleaning it wont help unless its as dirty as your EGR and jammed up but mine was just dead. good luck.

yuyo

SO I CLEANED IT AND THIS THE CLEANEST THAT I COULD GET IT... AS SOON AS THE SUN COMES BACK I WILL CHECK THE ICV (idle control valve)....

andyman32

The EGR valve is unlikely to cause oscillating idle speed - as is the idle air control valve. The ICV could cause the idle to be abormally high if it's stuck open, or low and lumpy if it's stuck closed, but it would have to be opening & closing at the same rate the idle is fluctuating to cause your observed symptoms. It's possible, but not likely. I'd be looking for a sensor. If all else fails, take it to a good independent shop (if it's drivable) for a diagnosis before spending hundreds of dollars on what might be the wrong part...

yuyo

yeah true the car is drivable but the tags are expire. I want to still take off the icv and at least clean it but this damn rain is preventing it but as soon as i get a chance i will post pics.... Thanks... But which sensors would i be looking for??????????

vdeleon

Check your MAF (mass air flow meter) if you have erratic IDLE RPM.

yuyo

so i took off the icv and this is what it looks like i can't tell if is bad but im in the process of cleaning now i went to a small shop and they told me check the Idle Body that it was next to the throttle body but i cant find and don't know what their talking about does anybody have any idea?????????

dvourthis

The way to test that ICV is to run positive jumpers to the two middle pins then ground the others. Mine was cleaner than that and it failed. Mine also ran just like yours. Just my recent experience. Rockauto.com had the part and it idles great now. If your MAF sensor is going bad I doubt it would run at all. I talked to a Lexus mechanic at the dealer and he said the ICV is a fairly common problem with this motor.