This is going to be very hard to describe, so i think that is why searching has failed me. But ill do my best.

04 TL 5AT 127k miles. During normal acceleration, up to 3-4k, everything is fine. However when I start to climb into the higher RPM's, it is almost as if the car is not smooth. It seems that I am just slightly letting my foot off the gas, although I am not. The possible causes that I can think of, which may be totally off the wall are-

-Not enough air is getting to the engine
-Fuel Pump/Filter
-Compression may be off
-Dirty injectors

The only maintenance I have done which may pertain to this is new spark plugs about 15K ago (NGK Iridium), seafoam within the past 10K, and timing belt about 18K ago. But i feel that I would have noticed this much sooner if it had anything to do with those.

I will try to think of ways to better describe this. Also, it is not extremely noticeable, as I feel that anyone else driving my car, besides maybe a mechanic, wouldn't notice it at all. I am open to any suggestions, and IHC, this seems to be right up your alley...

Thanks guys.

 

I'll get back to you in more detail when I get a few minutes free but here goes...

So are you saying it runs pretty normal but doesn't pull as hard from 3-4k and up?

I would first make sure vtec is working. Do you hear the change in sound when the manifold switches over to the short runners somewhere near 4k?

Assuming vtec and the dual stage manifold is working, plugged exhaust will make it fall off in the higher rpms. Usually due to melted or coming apart catalytic converters. I've seen cars that you could floor the gas in neutral and they wouldn't go past 2,000rpm.

Have you seen a loss in mpg? Any loss or change in power below 3k? If it's an automatic, does it seem to shift at a higher rpm than normal for a given acceleration? Does it shift harder than normal under heavy acceleration? I'm not looking at a transmission problem but this will help pinpoint if it's actually losing power in the higher rpms and making sure it's nothing to do with the TPS. If you lose power the transmission will feel like it's shifting harder.

Any difference from cold to hot?

 

1) Yes. It is almost like someone is quickly turning the AC on and off, every second, so i just loose that little bit of power.

2) Yes I do, sounds louder and more aggressive like it should.

3) Would there be a way to check this myself? Or would a shop have to? Also, is this a problem you or anyone else has had on 3G TL's?

4) None whatsoever.

5) Below 3k, nothing has changed.

6) Not that I have noticed, unless this has been a gradual change

7) Harder than it used to yes, but I have done 3x3 changes with Redline using Inaccurate's recommended formula on post 95 https://acurazine.com/forums/showthr...=834299&page=3

Thanks for the reply IHC.

 

I wouldn't do anything just yet, run a fresh tank of fuel through it, maybe from a different station. You're using 91 or higher, right?

 

OP, there's a TSB for ECU reflash for 04 TLs. Not exactly the symptoms you are describing, but may be worth a look.

Also, I'd get the codes read just to be sure nothing is being stored.

 

Yes. Using 93 and have been every single time.

Ill have to try the reflash. I havent in awhile. And which codes do you mean? Who would read them?

 

Reflash has to be done by a dealer. Almost any chain auto parts store will read the DTCs for free.