My 07 Acura TL has a rough idle after driving it 20 minutes or so. I could drive it down the street and it will be fine, but when i take longer drives (i drive about an hour to work every day) and come to a stop at a light or in traffic the car starts vibrating and the idle is between 5 and 6. Sometimes it jumps/jerks when im slowing down right before i come to a complete stop. It shut off on me 3 times-- twice while i was parking the car and was completely stopped (car was in Drive once and in Reverse once), another time while i was stopped at a light .. the car turned on perfectly fine right after. The check engine light does NOT come on. I took it to a mechanic and they said they couldnt pull any codes and cant figure out what the problem is until it gets worse. Also, I've had the car for abut 6 years now and this is the first time something like this has happened. The owner before me put in an air intake and the mechanic said water/dirt getting inside that could possibly cause this as well. I'm not a mechanic in any way so I'm not sure where to start. I did some research and saw something about an idle air control valve but i dont think an 07 acura tl has that does it? Saw something else about an EGR valve as well.

What can the problem be and where should i start first to get the problem resolved? Any help would be appreciated. Thanks

I've gotten the below done to the car --
- New motor mounts
- just got new spark plugs
- just did transmission flush

 

Lots of things can do that. Before you throw money at it, try some of the obvious things:

Did the problem exist before the new spark plugs? If not, the spark plugs might be the culprit. Confirm that you used NGK Iridium spark plugs, PN IZFR6K11 I believe.

Also, remove the coil packs and use some CRC electrical cleaner inside the spark plug connector to make sure it's clean.

Do a seafoam clean (through the intake) and a bottle of Gumout Multi-System tuneup in the gas tank.
.
Remove the MAP sensor from the throttle body and use the CRC electrical cleaner to clean it.

Make sure your battery terminals are clean and the cables are well adjusted.

Check for vacuum leaks. Look for any tubing that is loose or has holes from the intake manifold. You have one that goes to the front valve cover, one that goes to the brake booster and a few others that connect to the throttle body and intake manifold for various things like motor mounts and the EVAP system I believe.

Clean the EGR. It's relatively easy to remove. Use something like brake cleaner to spray it out.

If none of that helps, consider throwing a few parts at it, which might be things that would be a good idea to replace anyways:

Upstream O2 sensors (A/F ratio sensors). These are expensive however and usually throw a code if they're malfunctioning. However, they can get lazy over time and become less accurate. If you have over 100K miles on the car it might be a good idea. Use only OEM or Denso. Denso is the OEM manufacturer for Honda/Acura O2 sensors. Don't worry about the downstream sensors by the way. They have nothing to do with engine parameters, only exhaust pollution levels.

PCV. It's doubtful that the PCV is causing the issue but it wouldn't hurt to replace it. It's cheap and easy to replace.


If you want any instructions on those things check YouTube or ask Good luck!

 

 

Your very post prompted me to register and plant my very first reply. Anyway, similar case (same year&model) except I just bought mine from a used scum dealer. If I may suggest you start with the throttle body? Is it dirty? Does the butterfly valve open with ease if at all? How is the TPS? Throttle cable..etc? I would start around there..check for carbon build up...Check your air to fuel ratio too. Do you have a scan tool? Start checking the small stuff before spending big on parts you probably don't need to replace yet. For more details I suggest you watch couple videos on YT on throttle body and intake and get to know your car. Prepare to watch ALOT! It's fun!
good luck!

 

It certainly wouldn't hurt to remove the air intake and inspect the throttle body. CRC has throttle body cleaner which you can spray in there to clean it out. Or if it's really bad, you can spray some of the cleaner on a towel and clean it out manually. It shouldn't be too bad as long as you haven't gone without an air filter but still, in 150K miles it's likely to be a bit dirty.

The throttle body in the 3G TL is electronic (drive by wire). No cables.

And yes, it would be a good idea to pick up a cheap OBD2 Bluetooth reader off eBay or Amazon, then download the Torque app on your phone to monitor engine parameters such as A/F ratio's. If your long term fuel ratio is off by more than +/- 10% you likely have a problem.

 

@Grelins thanks! Did you find a specific solution for yours?

@losiglow thanks again!

Again im not a mechanic in anyway at all so i think i have to bring all this stuff to my mechanic because i dont want to mess anything up more, plus i dont have a garage lol its way too cold here on the east coast

 

losiglow yes you're right there are no cables.. found out this morning after insisting, to my mechanic, that the butterfly valve wasn't opening up on mine AT ALL unless I press aggressively on the pedal and that I wanted to replace throttle. He said those things don't go bad easily and I shouldn't be so jumpy to replace it. So when I mentioned then the accelerator cable (novice here) he corrected me that it's only sensor Which leads me to answer:

VikDakid23 I'm starting to feel a little confident that in my case it could be the accelerator pedal position(app) sensor AND a very VERY dirty throttle body...you should see the thing! I'm afraid of what the back side of it looks like. Basically there is NO/LOW air getting to the engine. I think while there maybe no air getting in.. there's still unregistered air from a vacuum leak.. which throws the fuel to air ratio off which throws EVERYTHING off. Our car's ECM/PCM is very sensitive. I'm dropping the car off at his shop tomorrow. Btw I had to find this out on my own after this same mechanic and others turn me away a month ago after I thought it was my transmission slipping. One mechanic said it was the temp gauge and charged me $200 lol. After him, I said no more and got to work researching what I felt and I found most likely the fuel trim was off. Really don't leave it ALL up to them. All they see is the $.

 

 

 

Also, now most of the time the rpm is above 1 always and when I let off the gas and let the car roll the rpm go up without me pressing the accelerator

 

Hello there!
So did your Mechanic "check it", took it off, cleaned it? What exactly did he do? This is important! The reason I'm asking because if he "checked it" without removing meaning touching/flipping the valve or sticking anything inside there then he might as well take it off...doing that can push muck further in..that can cause even greater an idle..I took mine to a NEW mechanic! Here's what I suspect he did ( i couldn't see but I heard at the end something which perked my ears):
Did you check your car after you took it back?
Here's why: if he cleaned the throttle body. He MUST reset the TPS to calibrate itself with the engine's computer or else you're going to still have that idle and it's going to be worse, for obvious reasons. Our cars talk through electronics. So if he flipped the valve sprayed some shit in there(sloppy work if you asked me) car's tps must be reset. if he took it off cleaned it and after putting it back on? Reset! Reset!! AND here's the key - you will know by your engine's rpm if it's a small shop, because they have to run the engine after..for a good while. This guy must have had a big brick seating on the gas pedal because when I heard the car turn I sat like a Doberman waiting in the room the engine revved and it just kept going and going..and going and going at high rpm for an uncomfortably 5 minutes and TWICE!!! he did it..with 15-20minutes segments. He left it idle for the rest of the while the last time and took for another 5 minute drive. And let me tell you that what and how he did it worked!!! My rpm when i start the car is now below 1000.(between 750 & 1000) but no more above 1000 or 1500. Now when I down shift it doesn't do the jerky jerk AS bad..but that's for another reason discovered recently. I guess that's how he resat mine.
Anyway, i would call them up and inquire..if they say.."i did what you asked" ask for specifics lol. IAC valve too must be free & clean. They must possess the tools/system to reset sensor...or else it can not be done! ✔ that's what this mechanic told me but I'm not sure I believe him 100%. How would these DIYers reset theirs? I sure have not seen or heard of anybody running an engine this long to reset tps but it worked and I wouldn't discredit his process. I'm confident you're having that rougher idle because they didn't do a proper job and I can only say that because I've experienced it.

Good luck my friend

 

Hello kindly disregard first portion of post, clearly you said he CLEANED it... moving along...

 

@Grelins i did some research last night and yea thats what i need to do. I need to have a mechanic reset the tps with a scanner and then do a idle relearn procedure which is what your mechanic did when he revved the engine for so long ..

 

Yes idle relearn. Thank you, I was wondering what the process was called. Can't these same people relearn it for ya? they cleaned it...or give you some money back.
Keep us posted!

 

Had someone with a scanner reset the TPS and do the idle relearn procedure and the car is back to normal! thank you both for your help @Grelins @losiglow !!