Hello everyone,

I have:
2005 Acura TL 5AT
80k Miles
Iridium Spark Plugs
Chevron 91 gas
Mobil 1 Synthetic 5W-20 motor oil


My car is rough idling especially on a cold start. I recently tried seafoam and it didn't fix the problem although it did get me 37mpg on the gas cruising at 70mph. Recently replaced spark plugs and motor oil. Any ideas?

 

This is a great question, I have a similar problem, mildly bad idle but plugs, oil, 3x tranny fluid change, seafoam, and redline SI-1 additive haven't cured it. pissin me off. Mine's 04 AT TL with 34k on it.

I'm going to try cleaning the Throttle body and the IAC thing, if someone'll tell me how to do it...

 

What part is the IAC? If I know where is was, I would clean it.

 

If under warranty, take the car to acura and have them check out the motor mounts and replace as necessary. If the mounts are fine, have them neutralize the motor. As well, have them preform an Idle Relearn procedure.

If not under warranty, check the mounts for cracks or leaks (there is 1 filled with fluid, if bad, replace them.
to neutralize the motor, do this:
1. loosen mounts to finger tight
2. turn on car and shift between park->reverse->drive->reverse->netural->drive -> park.
3. turn of motor and then tighten the mounts to specs.

Idle relearn
Make sure you have all the codes for your car (radio/nav)
Unplug the battery for 30 minutes. Then reconnect and enter codes, then have the car idle for 15 minutes with every accessory off, including lighting, a/c and radio.

 

OK this is the first I've heard of this, is there a TSB describing this? where'd you learn about this? I'd love to be able to fix the vibration, thanks!!!

 

There was a service bulliten about clunking noises and harsh vibration, and it mentioned the motor mounts and the procedure for engine neutralization. That is where I learned it from. As for the Idle re-learn procedure, are cars have drive by wire, and they adapt to the way we drive. Well an error can occur causing rough idling, reseting it is one of the easiest things to do, and this is required every time after the battery has been pulled for 15 or more minutes, as well as the auto up windows.

 

I would start with the simple stuff- spray clean, with carb or TB cleaner- the throttle body butterfly plate- the only moving part on a fly-by gen 3!
It naturally gets oil vapors, and crud sticks to that- then it doesnt seal correctly and disturbs the airflow. Simple DIY to clean

If the plugs were recently changed, were they the correct NGK Iridium for your year?
The ignition coils on the spark plugs are oddly delicate and easily damaged during plug change
Stop by autozone type store and ask them to pull and codes- its free
If you have misfire codes- guess what has a problem!!

 

thanks everyone for your suggestions, I will try them...and no I do not have warranty as of now. The car seems to run much better when it is warm...although still rough idles. the ngk iridiums are correct for my year and ignition coil seems to be fine. I don't have CEL come on, will the ODBII show any code?

Anyone know where and how I can check the motor mounts?

 

if thats the scan tool that pulls codes- that will show if misfire codes
the coils will show no visual clues and may only be a weak one... not dead yet, seen that recently

 

Do you happen to have the procedures of how to clean the throttle body or suggestion? thanks.

 

I have an '08, so I have not done it on this car. But I did it on my '05 Honda Pilot 3.5L VTEC, so I imagine they are pretty similar.



Here was my post:

The dealer wanted $100 for a cleaning and $36 for an air filter. So, I went and got an air filter with a can of Valvoline throttle body (TB) cleaner. $15.00 later, I was ahead of the game. The TB looked fairly clean, but I sprayed and wiped and replaced the air filter. You need to remove the plastic engine cover, lossen the clamp over the TB, remove the air filter body. The whole apparatus moves without havng to disconnect other "attachments". Here are links I used:

http://www.mobiloil.com/USA-English...tle_Bodies.aspx

http://www.hondaclub.com/forum/artic...-cleaning.html

 

thanks millarduck, very helpful information.