I need some help folks. I have a 13 SHAWD TL with 10k miles now. For the last 5-6k miles I have noticed that the power has been down. I can best describe this as slow off the line (with the engine sounding louder and up shifting slower than usual) poor merging power, generally rough. This however is intermittent but it is becoming more consistent now as miles keep climbing. The frustrating part is that no CEL is on. The dealer says that no codes are pulled when they connect the diagnostics. I had mentioned this in this forum earlier but didn't get a good response. This is driving me nuts now. I am having an underwhelming ownership experience as I am constantly reminded of something being wrong with the car. The fact that this is intermittent makes me believe that it is a sensor or a software related problem. When it runs great it is a pleasure to drive. I have always used 93 octane fuel and I have kept up with the one service reminder so far. Everything is stock and I have a spirited driving style. Any ideas? I was thinking it could be the knock sensor that is somehow not letting the engine timing be ideal for max power. Any other ideas or similar experiences? Anything that can be done at the dealership for this? Like can they check timing with their scanners to see if it is off?
Thanx

 

Try disconnecting the negative battery terminal and wait a couple minutes before reconnecting them. Then let the car idle for about 5 minutes, then go for a spirited/aggressive drive.

I know when I bought my 13' TL, I babied the crap out of it for the first 3000 miles (never went above 3k). Then after that, I installed a SRI, so I disconnected and removed the battery for more room. Then did what I stated above. It's hard to describe, but these drive by wire systems seem to learn/adapt to how the car is being driven.

 

also, heat kills power.
as we are ending the summer, i wouldnt be surprised if it gained back its peppiness.

silly questions; only use premium fuel? 93 or better!!
Jackie is right, the ECU learns the driving habits, try resetting the ecu by disconnecting the negative terminal on the battery for a few mins.

again, it could very well be the knock sensor and the ecu scaling back timing.
this would indicate heat soak or the need for higher octane.

 

Agreed...I thought it was heat soak too but now with the temps in the 50-60 in Chicago there is no improvement. Also I use only 93 octane and no less and same gas station. Now here is the kicker.. As I told you performance is inconsistent, it drove normal or with max power on the hottest day recently when temps were in the high 90s. This makes me believe it is not hear soak. I will disconnect the terminal and see the response. Now if it does gain full power with the ECU what are we ruling out? ECU related issues, sensor related problems?
Also I don't baby the car I have a spirited driving style hitting 4-5k at least once a day.

 

Will disconnecting the negative battery terminal reset any of the saved functions on the car (i.e. radio stations, seat positions, key settings)? Will it require you to enter any radio codes to unlock it?

 

yes, you need the radio codes handy.

 

how is fuel economy?
please include average MPH and average MPG according the MID.

 

Average MPG:23.2(75 hwy, 25 suburban state routes). Average speed 38mph. This is averaged over 10500miles.

 

Codes are located under the lid of the fuse box in the engine compartment.