Got the exhaust installed Friday morning at Lexus of Westminster, and today went out to SGV from the SFV, ~130 miles total today put on the exhaust. So far I've put on nearly 300 miles these past few days and I'm noticing I'm getting worse mileage ~23 mpg compared to the 25-27 I had been getting previously and the car overall feels more sluggish. This happen to anyone else, or should I bring the car back to Westminster?

Or is this a sign of the dreaded Carbon Buildup??

Still sounds awesome, but feeling performance is not too awesome currently.

Update:
It was due to having ~500 lbs extra worth of passengers haha

I don't know what to tell you about the mileage. Regarding the sluggishness, I'm guessing it can be attributed to the fact that your car now sounds much more aggressive, it's only natural to feel that it should be faster than it actually is.

ehhh...its in your head.

You've been hitting your gas more often and slighlty harder. It happens.

In fact, I was getting 25 mpg my last tank but only got 19.5 this tank.....so just enjoy it and dont worry.

I feel like I have to put more force on the gas pedal to get it going the same speed, on freeways it was fairly easy to cruise at 80, now I have to put more effort to cruise at that speed. I have a feeling it's something else that is happening and is coincidental.

ITs all in your head. Noise does wonders lol.

The car today feels fine. Realized it was because of the passengers haha. After I got the exhaust installed, I drove with 3-5 people total in the car, hence the sluggishness from the extra weight. Today just drove by myself to work and it felt fine.

Haha didn't even consider it 'til now...

500 lbs of weight will do that...

haha...get thinner friends

I wish they were friends, they're family I have no choice. haha
Just kidding!

lol...you're killin' me

hahahahahah i thought the same thing when i had a car full of my 250lb buddies. i was like wtf!

Yeah...it's all in your head. With a new exhaust you might have been more prone to drive a bit more aggressively. :-P

Car drives the same, if anything feels more efficient. Most of all, loving the sound haha.

*whew* You had me worrying for a second there Jeff.
Happy to know that you're enjoying it still!

Bumping this back up.

Brought the car to Lexus of Westminster where Pete took care of everything.
After getting the top engine cleaning/carbon buildup performed, got 5 mpg improvement for overall avg and 6+ mpg improvement for tank avg after 2 tanks.