thegipper

04 TL 121k miles.

Plugs were replaced last year, checked torque of the plugs a few weeks ago. WIX air filter replaced last year.

No CEL, otherwise runs great.

Occasionally (maybe once every 7 start ups), my TL will feel underpowered on acceleration at lower speeds up to like 65mph. It isn't fumbling or idling rough it just feels sluggish, and it only does it shortly after starting the car. I have to push the gas peddle down further than I would normally have to. Transmission isn't slipping or anything it just is bogged down. Once I've driven it for a few miles, its running normal again.

Anyone know why this is or what I should check?

Thanks guys

thegipper

Ok so I did some more searching and I found a couple other people with similar problems. This is what I found.

Possibly a bad IAT (intake air temperature sensor)

Possibly a bad PCV valve

Possibly a bad EGR valve

Anyone agree or disagree with these three?

Another thing it does sometimes is start a little rough for the first second, then it immediately goes to the correct rpm and idles fine. It also only does this once in a while, maybe once a week.

Thoughts? I appreciate the input.

pbook4g5

There's been quite a few of these threads popping up this summer, with me making one of them. In my research, I've found the lack of power issue to be somewhat normal with these cars.

EGR valve malfunction would throw a code, although its easy to pull off and check to see if its clear. PCV is a $15 part and super easy to replace, although it shouldn't cause sluggishness to the effect you're talking about.

Things we've gathered from other threads are O2 sensors, the MAP sensor, or the APP sensor.

Do you have an AT or an MT?

thegipper

It's an AT. Once a long time ago, maybe a 2 years ago, it did throw a bad 02 sensor code. I erased the code and it never came back.

Think a bad 02 sensor would cause that and not throw a code?

One other thing, today when I was leaving the store, it did it again. Seemed sluggish/bogged down and I swear I smelled a faint, i mean faint, smell of gas. Almost like it was running rich. Could be losing my mind but whatever it is, seems to be happening more and more. Only a 20 or 30 seconds later after I hit cruising speed, it was back to running fine again. Came to another stop light and it accelerated normally.

Thanks for the input

pbook4g5

If anything, a few of us think the car is leaning out when its being sluggish, which is why we think an O2 sensor could be the cause.

The sad thing is a few of us have tried all these various things and there doesn't seem to be a magic bullet. What works for one doesn't work for the other. Although I dont know of anyone who's tried changing the MAP sensor.

thegipper

So if you were me would you replace the PCV valve first because its cheap? If that doesn't fix it, 02 sensor next? Then APP?

I'm going to check the cable tension on the APP first.

I hate throwing parts at a problem but if there is no other way to find out, I guess that is my only option.

pbook4g5

How is your oil consumption? Do you have to add between oil changes? A stuck PCV will likely suck oil back into the intake. I'd PCV and then APP, but start by checking the slack on the APP first like you mentioned.

thegipper

No oil consumption what so ever. I'll check the APP cable slack tonight, then replace the PCV because its so cheap.

I'll report back if it fixes the problem. If not, may do the o2 sensor next, which reminds me, should I replace both or is there a specific one I should replace? Or I'll replace the APP.

thanks

pbook4g5

I'd start with the upstream sensors above the Pre-cats, but honestly, I think that might just be throwing parts at the problem. I don't really think its the O2 sensors, but again, I really don't know.

I'd start with APP after PCV (and I don't think the PCV has anything to do with this specific issue you have since oil consumption is ok).

thegipper

Sounds good, I'll do that. Thanks for the help!

thegipper

I checked the APP cable yesterday and it had a ton of slack. I snugged it up and took it for a drive. Wow, what a difference. So far no sluggishness but I'll report back in a few days and let everyone know if the sluggishness ever returns.

thegipper

Well everything was gravy until today. Had the sluggish acceleration happen twice today on my way back from work.

Looks like at this point I should try replacing the APP, I'll report back if it ultimately solves my problem.

thegipper

Ok I finally got my new APP sensor and installed it today. Took 10 minutes tops to install and took it out for a drive.

I immediately noticed that the acceleration was smoother and more consistent. I haven't had the acceleration for a couple weeks now (it has been cooler here in WI, that may have something to do with it) but it didn't have any issues during the 10 minute drive that I took it on. From face value, it appears to be driving better with the new APP sensor.

I will report back in a month or so or unless the problem comes back. Crossing my fingers that the issue has been resolved.

pbook4g5

Good news. Thanks for the report back. I ordered my APP four months ago and still haven't installed it. I'm lazy.

thegipper

Another update:

It's been about a month and so far, not a single instance of sluggish acceleration. Keeping my fingers crossed but it appears my problem has been fixed with replacing the APP.

I'll report back if anything changes.