kylem61

Hey all, so i've got an 04 manual TL with 149,000 miles on it and I've owned it for a few months now with no issues. Recently though, it started jerking/bucking really bad when accelerating in 1st. It's usually somewhere between 2000 and 2500 RPM when i'm accelerating, it will start bucking real bad and the RPMs bounce around a little (maybe 200-300). It doesn't happen every time I accelerate but it has been happening more and more frequently it feels like.

I did some research on AZ and originally thought it might be the APP sensor but it only happens in 1st, not in the higher gears which, correct me if i'm wrong but the APP sensor issue would be independent of gear. But either way, since 1st is such low speed I wasn't able to check it by activating cruise control. I ran it by my old man and he said it might be the MAF sensor just needs to be cleaned. Hopefully going to get around to doing that soon and see if it helps but I was just curious if anyone else had any thoughts/ideas what it might be?

Nytetime6

Hmmm, my car is doing the same thing. I have 153,000 miles. It seems like the problem goes away once the car is warmed up.

NoTLoud

If the RPM's are jumping around, it could be the MAF sensor or potentially something else causing the air fuel mix to be off or read incorrectly. But I believe RPM surging like you are experiencing is a common symptom of a bad MAF sensor.

I believe the common symptoms of APP sensor failure are basically input lag, so when you hit the accelerator, it will take a second for two for the car to recognize that. You can remove the cover to the APP sensor and check the cable running to it. There are two nuts that you can use to adjust the cable. You want it pretty tight. However, RPM surging is not a symptom I have read for APP sensor failure.

Just noticed you live in Blacksburg! You going to VT? I was up there the other week and had parked next to a TL that was a 6 speed, would be hilarious if it was you.

Nytetime6

Do you mean the MAP sensor or do our cars have a MAF sensor?

NoTLoud

horseshoez

iTrader: (2)

Correct, they both do so by very different means; the MAF uses a hot wire to determine the weight of the intake charge, the MAP uses barometric pressure to do the same thing.

kylem61

Ok, I will check out the MAP and see if maybe that's the issue. So you think the sensor itself is bad, am I going to need a new sensor or is it a fixable issue with the one I have? But yeah there's no lag necessarily, it just feels like I'm on and off and on and off of the throttle when I'm really holding constant throttle. But what throws me is that it has only happened in 1st...

And yeah, NoTLoud, just finished up my Bachelor's in ME at VT. Ive seen a few 3G TL's around town but mines a black 04 MT so might've been mine, haha.

Nytetime6

Online there are some videos that show you how to clean the MAP sensor. I will try to do that first before buying a new one. I may try it this weekend. Its weird because when my car warms up it no longer surges at stop signs or stop lights. When i first start the car and drive for a bit then I can feel it surging.

kylem61

Yeah, mine is similar. It will still do it maybe once in a while after it's warmed up but it is mostly in those first couple accelerations after pulling out of the driveway when everything is cold.
​​​​​​​Also, I noticed it hasn't always been starting up on the first time either. That could be a number of things but I'm wondering if maybe that's another symptom of the faulty MAP sensor?
​​​​

Nytetime6

On Saturday I decided to a idle relearn. So far it has solved the surging bucking issue.

Here are the steps I took for the idle relearn:
Unhook the negative battery terminal for 30 minutes. (make sure you have the radio and/or navi codes)
Turn the key in the II position for 2 seconds . (make sure all accessories are off, radio, climate control etc)
Start car and rev the engine at 3000 rpm (while in park) until the radiator fan kicks on.
Let the car idle for 5 minutes.
I took and additional step of letting the car idle 5 more minutes with the a/c and radio on.

So far so good. I don't have the surging issues that I've did before.

kylem61

Update: I think its the APP sensor. I was on my way back home from the holiday weekend and while driving on the highway the check engine light and both VSA warning lights came on and the throttle fluttered a couple times. Restarting the engine reset the VSA lights and the CEL eventually went back out but I fished around a few threads on here and read that its likely the APP sensor going bad. Had Advance read the code, they confirmed that it was the throttle position sensor error code so I went ahead and ordered a new APP sensor and plan to install it in the morning. I will post an update but hopefully this fixes both issues.

Nytetime6

When my car went into limp mode I got code P2101. The dealership cleaned out the throttle body and installed a new airbox and I havent any issues since with the limp mode. I think the dealership didnt do an idle relearn after cleaning the throttle body which why I had surging an bucking issues.