I looked through all the problems on this site and did not see it. Here it goes. After I start my 2003 TL Type S when it is cold and run it for about ten minutes and come to a stop the RPM's drop to around 500 and the engine runs rough for a second and then the computer adjusts the RPM and it returns to 750 where it should be. This will only happen once or twice then it will be fine. Any help anyone can give would be greatly appreciated. I have not had the dealer look at it yet. So far it has not been that bad, just frustrating.

 

I would try cleaning the IAC valve located on the bottom of the throttle body

 

I am having a similar problem, but mine does this most of the time at a stop, or idle.

I am not sure if it is a coincedence, but I also have a SERVICE ENGINE SOON light on and the TCS light comes on 90% of the time after driving for a couple minutes. The TCS light is off at start, but comes on after driving a while. I am going to have the codes pulled today and will post the codes later. Just wondering if this is two different problmes or not.

 

get the codes read then we can help you better.

 

sounds like what happen to me about a month ago, but my idle was going crazy up and down and the TCS and engine check light came on to. before you go spending any money on repairs, just rip out that throttle body and unscrew the IAV valve. give that a good cleaning and go from there with carb cleaner. oh yeah, you might wanna reset the ECU after that to.

 

I have heard this before...I believe the almighty fsttyms1 said this in a previous post. Again... I need a little help with where on the throttle body this valve is located. A link would be great.

 

On the bottom.

Part #2

 

its real simple. the throttle body has 4 bolts. turn it over and there is the IAC. it took me 30 min.

 

would you guys say that cleaning the IAC valvew and throttle body more than likely could fix a idling problem because my idle problem is when I drive the rpm tach tends to go up and down which makes the car stutter, and my car is fairly new its 03 tl-s with 40k miles. thanks

 

I finally got the code. It pulled a P0131 O2 Sensor, bank 1 sensor 1. It also stated that the sensor was pulling low volts. My local Autozone has an oem bosch upstream (which the guy behind the counter indicated was correct because bank 1 was upstream) for $102. Does this sound right, and if so how does the price sound?

 

I had the same problem with mine earlier in the year, but the dealer took care of it due to my remaining factory warranty. They replaced the egr & idle valve and the problem was gone.

This is a nice car!

 

Emissions warranty is 8 years 80k miles- maybe more miles in some parts
Anything that would cause car to fail smog is covered, from cats to O2 sensor
Drop by and talk with your Service MANAGER--- NOT the service Writer

 

There are many posts in the forums that deal with this subject (irregular idling), but this thread has a nice diagram that I found very informative.

I think a good thing to pay attention to is WHEN the car idles, hot outside, cold outside, when the car is cold, when the car is warmed up etc.

For me the problem was when the car was warmed up. The problem was very subtle in the beginning, I thought perhaps it was an electrical problem. The idle speed would fall to the lower rpm's and jump right back up immediately after I would try to roll my driver's side window up (surge in the electrical system). Ultimately the problem become so worse that this would not affect it any longer.

So i took apart all the necessary bits and pieces until I found the IAC.

I am still not sure why it was recommended to use electrical contact cleaner in the other threads and not a carb cleaner since there was a great deal of carbon buildup. I realized about 5 minutes into cleaning that this was going to take something a little more aggressive, either chemically, physically or both.

I employed q-tips into the process of cleaning and found that was a little better but not quite..I was still uncertain "what" clean was. turns out there is a small rotary valve (think of it as a cylinder with a tall wedge cut out of it) that allows air to pass through it when it is rotated by a solenoid.

To make a long story short, I disassembled the solenoid from the valve, and continued to clean until I was able to get the valve rotating freely again.

Put all the bits back together and I ran the car around the block for a while and checked the idle speed at all stops..all is well again.

Not sure the consequences of disassembling the solenoid, so I'd try that at your own risk. I will let you guys know if I screwed it up. So far so good though.

Why in the world do they make the parts most likely to go out so hard to get to?

 

The only place we would have recommended electrical contact cleaner would have been on the actual connection. carb cleaner should have been used on the valve itself for the carbon buildup.

 

Well guys I tell you this In the cold my car doesnt do that guessing that the weather plays a factor in it. But when it get 60 degrees and up my car idles from 5 to 6 THOUSAND RPM'S at PARK when I try to shift it wont let me. I have to turn off the car let it cool off so I could drive off. Imagine that happening in NY traffic especially during rush hour. WOULD THE EGR AND IDLE VALVE WOULD TAKE CARE OF THIS PROBLEM? because I took it to the dealer and they cleaned the throttle body and they could'nt find nothing wrong. Need feedback guys I mean I know you feel my pain too