My 05 TL has 103,000 miles on it. When I make a stop, or just put the car into gear the RPM's drop to about 500 and it vibrates much more than I expect. I have never noticed this before.

I have just changed the plugs with the correct new ones, this has not corrected the problem.

Suggestions?

 

If its an auto, you should have your transmission.

 

It is an auto. I should have my transmission what?

 

does it vibrate and hesitate also?

 

It doesn't seem to be hesitating. It only vibrates or "rumbles" when the RPM's drop to around 600. They pick back up just after it does this, then you can barely tell the car is running. It does this when I put it into gear, or stop at a red light. The rpm's drop, the car vibrates, they pick back up about 100 then it's fine. It is only at low RPM's that I feel this. Should it be dropping RPM's like this when I stop? It seems to drop just as I completely stop, then pick back up a bit.

 

check your motor mounts

 

Oh sorry, check your transmission. When it does that, its signs that your torque converter is worn or going bad. Its just warning signs before it begins to slip.

 

Does the car's RPM drop only to around 500/600 while in drive ONLY or is it doing it when the car is in park or reverse as well? Does switching to neutral help at all?

When is the last time you disconnected the battery for more than a few minutes? Unplugged while you changed the spark plugs? Which ones did you use?

In all honesty I think that you disconnected the battery for about 1 hr or so during the spark plug install and never redid the Idle Relearn procedure causing your problem. To fix it, disconnect the battery again for about 30 mins. Then reconnect and turn on the car to stall mode and turn off all the accessories such as the radio, a/c, lights, etc. Then turn the car on and let it idle for 15 minutes. This will make the ECU re-learn its' proper idle and fix it dipping it down to 500/600 when it should idle at around 700/750

 

If you disconnect the battery, the car requires a "Idle Relearn Procedure" where you let it idle for 15 minutes so that it can relearn the idle points.

 

The batter terminal became loose the other day, I did not know about the idle learn procedure. It seems to do this in other gears also, btw. I will try the relearn procedure to see if that helps and report back.

 

The relearn procedure worked! I took a drive around town with the a/c back on and all, seemed to hold 700 rpm range perfect! No more vibrating/rough idle. Thanks!

 

Now if I can just remember my radio code :/

 

it could be possible that one of your spark plug gap may be incorrect. they should all be at 0.44. the ngks plugs usually are pre-gapped from the factory but i would double check

 

Glad I could help and that all is well again.

 

it happened on my 00 Accord in the past. I took it to a mechanic and he took out the air filter box and the "hose" connected to the engine and clean it a little bit and everything seems fine after that.

It cost me $35 to have it fixed and I hope it will be easy fix for you.

 

It's fixed already. Was a easy and free fix thanks to the help of the members.

 

I realize this thread is from last year but I felt compelled to comment and thank you for the ‘idle relearn’ tip. I didn’t notice my 3rg gen TL idling as rough as it was when I bought two weeks ago. To be honest, I was worried that I may be shelling out serious dough for a fix. But this magic trick did wonders and now my car is purring really smoothly. This forum truly rocks and thanks to all those knowledgeable people for helping us novices and sparing our wallets!
Cruz

 

^basically a ECU reset.