Hi all,

I got a TL-S with about 95k miles and my Idle speed drops from 750 down to 500 or even lower then goes back up to normal. The cycle repeats every couple of seconds.

I noticed when RPM drops the dash board lights dim and motor shudders. After driving for about an hour the issue seem to go away until the car is cold again.

With a slight throttle or during normal driving I haven't noticed any RPM drop.

I searched the forums and I've seen similar problems but not exactly this one.

Do you have any ideas what to look for?

 

https://acurazine.com/forums/showthr...ght=rough+idle

check out this thread, might help out

 

Time to clean the IAC.

While you have the throttle body pulled apart, now is a great time to do some modding

 

Id start with cleaning the IAC valve

 

Thanks for the pointers. But looks like I scared it. The idle is normal now. I wonder if I had bad gas/water or something. If rough idle comes back will try crack this baby open.

 

Idle Air Control Valve or Throttle Position Sensor. I've had the TPS sensor do this more that the IACV.

If you clean your IACV and it stops you're golden. If it doesn't stop unplug your TPS while the car is doing it's auto-rev thing. If it stops when you unplug it..... your TPS is dead.

 

This is the problem I'm having. When it's cold out and I'm in Drive and stopped at a light, the rpm's will drop a little bit and the car feels like it is pushing forward, and then the idle comes up again. After I've driven for 10-15 minutes, it's fine and there are no idle problems.

So far, I've cleaned the egr ports and cleaned the intake manifold. This weekend I cleaned the throttle body and the iac valve by taking everything off (I had to pull the airbox anyway to replace a bad driver's side wheel speed sensor) and using carb cleaner to get all the gunk out. The iac was definitely dirty so I thought cleaning it would take care of it. Nope. This morning (it's hot, too, at about 45 degrees) I'm still having the same problem. Normally it's well below freezing, maybe single digits.

Is there a way to check the tps or iac with an ohm meter or anything like that? The car doesn't show a CEL and autozone couldn't pull any codes. It's very frustrating.

 

I have the saem problem. Sometimes its BAD. Car almost stalls out. I just cleaned out the EGR port a little while ago but didn't think about the IAC. Generally speaking this should clear it up?

 

Oh yea I forgot to mention this happens only after I'm parked for a while and as soon as I give it a rev or 2 the problems fixed. Its not enought time for the engine to warm up so I don't know if it has anything to do with the engine being cold. Could this be a fuel pump problem or something like that?

 

I cleaned out the IAC and it didn't help. Has anyone solved this one?

 

It may be a TPS sensor issue. I dont have my manual here to see what the testing procedure is, but if it is bad you cant replace it. You have to replace the whole TB.

What year is your car? Have you disconnected the battery lately? Mileage?

 

2000 TL. I have not disconneted the battery lately. Mileage is 126k. The tranny has been replaced with the post 2005 model. Any help would be greatly appreciated.

 

That sounds like the butterfly valve on your TB getting stuck. It has some gunk in there causing the valve to stay open and not closed when parked. When you hit the gas, it makes the valve shut all the way like it should be, and the RPMs go back to normal. Try and clean out the TB with some TB cleaner (in a spray can) from an auto parts store.

 

What do you mean that it feels like the car is pushing forward?

 

Probably when the RPMs jump up, the car kind of lurches forward b/c they don't have the brake pedal pushed down all the way.

 

Foot's on the brake, but it feels like you have the emergency brake on and you're giving the car just the tiniest bit of throttle or that one foot is on the brake and the other on the gas. It lasts for probably just a second or two per push forward. It will keep doing that at a stop until the car heats up. Also, every so often and shortly after leaving a stop, I will push on the pedal to accelerate, but the car goes no where. The pedal is down and the engine doesn't rev or stumble.

It drove fine today. Though late tonight (while I'm hard wiring in the radar detector, which was a success), I let the car idle for a bit in park (no surges or noticeable fluctuations in rpm) and the CEL came on. I'll take it in to autozone tomorrow to get them to pull the code. Hopefully, my cleaning did enough damage to finish off a bad sensor and didn't kill a different one.

 

this problem seems to be happening alot lately, i think the people at acura just decided to hit the self destruct button on our iac's so that we all go in to replace them for a premium.....damn conspiracies

 

Did you replace your IAC?