My Ls 2010 goes from 20- 21mpg to 16-17mpg since two weeks ago. No lights, no change in behavior, nothing to concern.
Mpg is combined. Same fuel, same driving habits. Tire pressure is ok. Car have 42k miles on it.
What would be the cause???

 

WOW. That is drastic. Try to run a OBD scanner to see if any PENDING codes are stored. If not, I would start with air filters, MAYBE spark plugs (though 42k is low for Iridiums). Maybe clean the MAF and throttle body.

 

Also try running a fuel injector cleaner through it.

 

Any chance someone siphoned some gas out of your tank? It's starting to get more expensive these days, and I think prices are going higher.

 

 

Maybe change the oil. Usually get my best mpg with fresh oil. What's your oil change interval and when was it last changed?

 

Thanks
No work done recently
Will run OBD, but right now no lights in the panel.
I buy the car 2 months ago. Full Lexus service, I have the records, I take a look.
Car performs exactly the same since I have it, no change in performance-behavior...
Will change oil
Any more suggestions.

 

Mmmmmmmmm???
Appreciate this forum.
Thanks