I have a 2007 TL-S, auto, 45k miles. I bought it in the spring and first thing I noticed was that it started a bit rougher than I would expect a 3.5 RL engine to. I carried it into the dealer and they said they cleaned the throttle body. I could tell a change for the good.

I live in TN and it has been in the 90's for the past couple months with about 70% humidity. Since the elevation in temperature I have had worrisome issues starting the car. If it sits in the parking lot throughout the heat of the day it 'misses' when I first start it. I can start the car, put it in reverse and the pedal will go all the way to the floor prior to 'catching' up and moving backward. I have even had it provide that same hesitation once I have it in drive and moving forward. After 15-20 seconds it seems to run fine. Though, I feel that I may have noticed the hesitation taking off from a red light once or twice.

If I have the windows down in the car, I can also smell a rich engine smell when backing out of the parking spot. I do not smell this later in the drive.

I took it to the local dealer last week and they told me that if ANYTHING were wrong with the firing of the car that I would have alerts. They kept it all day and said they could not reproduce. They said this car runs rich and should give me the 79 Datsun smell when I start it. Told me to come to a complete stop before switching gears, change the gas station I am using, etc. All irrelevant to my situation really. I already do this.

I am carrying it back this week and would appreciate any advice you can give as I am sure they will keep it for days only to tell me nothing is wrong.

I have also monitored the RPM's during this issue and can see the needle fluctuate barely. Barely.

TIA.

Mo.

 

i know some of the 04+ model TL will intentionally misfire to heat up the precats I do not know if they carried that to the later models are people didn't like it.....

 

These models do intentionally misfire to light off the cats quicker but your problem seems much worse.

One thing first, you're giving it throttle before the transmission fully shifts into gear???

From your description it sounds like it's running rich and you say it smells like it's running rich so I guess it's safe to assume it's running rich.

It may have been doing this for a while and the spark plugs are just getting fouled enough to cause a misfire. You can change them out to try and restore performance but until you get the rich issue fixed, you will eventually fould the new plugs.

The ECU detects misfires but it's not going to throw a code and a light for every single misfire. There are certain parameters that have to be met for it to throw a code or you would have tons of TLs at the dealership under warranty for check engine lights as every car will misfire now and then.

You could have gotten a bad batch of fuel. I would run it until it's at 0 miles and then put a full tank from a busy name brand station and see if it starts to clear up after a few miles.

The only thing that's odd is that it does it only when cold which really sounds like fouled plugs. You can start by pulling a plug to see what it looks like.

 

Thanks for the replies, guys.

No, not at all. It feels that way though! But I let it get into gear first. The car will actually move somewhat while it is doing this.

I hope it is as simple as a fouled out spark plug. If you say they are worse when cold, then this for sure seems symptomatic.

I am dropping it off Monday (first day they could have me a loaner). Maybe they will be able to recreate after having it for several days. If they do, I will be sure to update.

Thanks again for the responses!

Mo