When I bought my tl, I made a trip to PA the same day and the car felt light and fast but after changing oil with synthetic mobile 5-30 it feels slower and heavier. I have run over 500 miles on this oil change. Is it too late to go back to 5-20? Total millage is 104+k. I find myself stepping more on the gas as a result of this.

 

I have no idea why you'd be experiencing this, but you'll have no problem switching back to 5w20, or going back to dino oil as well.

 

I also change the tires on the car but I think I started noticing the problem after changing the oil. Which oil should I use if my car has 104k miles?

 

A 5w-30 will not cause any noticeable decrease in performance or mileage. Probably around .00001% at the very most. Plugs ever changed? How about air filter?

The 5w-20 specified should be fine.

 

They did a check at acura dealer a week ago and didn't mention air filter so I guess its fine but I'll double check tomorrow to see if it is dirty. Plugs werent changed.

 

seafoam
replace oil
replace plugs
replace air filter