Need help

Hey everyone,

Just got done changing the water pump in my ride. Talk about a PITA. Well after that I just figured I'm going start tinkering with this ride & doing some mods. Anyway, I have a 2001 4 door but not sure of the model, here's my problem. When I come to stop light & in idle, the car starts to vibrate real rough & if I have the a/c on it just gets worse. Now if I put it in neutral if stops. The motor mounts seem to be in good order. I've heard of an Idle Air Sensor but not quite sure of what it is or where it's located. This had happened before & I had to replace a broken hose that was about 2" in length of the front of the motor. Didn't know what it did or nothing but as soon as I replaced it, the motor ran fine. I had hoped it was the same thing this time around but no luck. Any help would be greatly appreciated & sorry about the long post.

[freeze12]

Since You just replace the water pump,when you reinstalled the timing chain is it possible that you installed it a tooth or so off so that now the timing is off causing the rough idle?

no...it was like this before I replaced the pump.

[Spilner521]

I don't know if anyone else has noticed, but the 2.4 vibrates a good amount when it idles real low. Mine vibrates enough to rattle the exhaust piping when it idles lower than 750rpm, but that's only because the piping is so big. When you put it in neutral the load comes of the engine and the revs raise a little thats why the ratting stops. If your mounts look good I wouldn't worry about it.

The Idle Air Control sensor decides how much air to let in to idle the engine when the throttle is closed. If there was an issure with that you'd most likely get a SES light.

[MixtapeMessiah]

Originally Posted by Spilner521

I don't know if anyone else has noticed, but the 2.4 vibrates a good amount when it idles real low. Mine vibrates enough to rattle the exhaust piping when it idles lower than 750rpm, but that's only because the piping is so big. When you put it in neutral the load comes of the engine and the revs raise a little thats why the ratting stops. If your mounts look good I wouldn't worry about it.

The Idle Air Control sensor decides how much air to let in to idle the engine when the throttle is closed. If there was an issure with that you'd most likely get a SES light.

Mine vibrates to hell when im at idle at a light or something and the engine is warm, otherwise its strong at warm up, then falls flat on her ass. My tranny mount is goin just havent replaced it ye.

Originally Posted by MixtapeMessiah

Mine vibrates to hell when im at idle at a light or something and the engine is warm, otherwise its strong at warm up, then falls flat on her ass. My tranny mount is goin just havent replaced it ye.

Mine vibrates like crazy as well. I've had this car since pretty much brand new & it wasn't always like this. I did locate the Idle Air Control Valve & the Hayes manual described it's function exactly as Spilner521. I removed it & cleaned all the carbon off of it & it didn't make a difference. I'm going to try & replace it & see if it helps. It would seem that this valve has a plunger type of deal on it & maybe it's not moving freely anymore. I just can't imagine that I have to keep putting the car in neutral for the rest of it's life.

So I'm not going to be changing my idle air control valve. It's $140 & I can live with the shake for that money (for now). If anybody else has any ideas please let me know.

[Gr1m]

just wait for a SES light to come on and get the codes read :-/

[Vinalero]

When does your car idle below 750 rpm?

My 2.4 idle at 960-970 rpm. It never goes below that.

[Spilner521]

Originally Posted by Vinalero

When does your car idle below 750 rpm?

My 2.4 idle at 960-970 rpm. It never goes below that.

After the car warms up and when it's in gear and I'm on the brake at a stop light or something, then it'll drop just below the 750 rpm line. It idles very low and very smooth, other than the fact that it rattles the exhaust piping. When it's in Park or Neutral, it'll idle at or just above the 750 line.

[Cliff8928]

Originally Posted by Vinalero

When does your car idle below 750 rpm?

My 2.4 idle at 960-970 rpm. It never goes below that.

The automatics idle lower than the 5-speeds.