So I went from full synthetic to a semi synthetic blend when I did my last oil change, now I've noticed that my gas mileage has gone to hell! Can the difference in oil cause this since it's oil injected? I recently (two days ago) put a new K & N Typhoon air intake system in, and am wondering what other options I have for increasing my gas mileage if possible. Any suggestions?

 

It's the intake.

You are using your right foot too much.

Clean the MAF, reset ECU by pulling room fuse.

 

K&N.
check the maf screens or clean the sensor.
You're probably enjoying the sound of the intake so you're mashing the right pedal more then you used to.

The oil has nothing to do with it.

how many miles on the car? how old are your plugs?

 

The plugs were new as of April, I cleaned the Mass air flow sensor when I put the new filter on... Car has 75,000 on it.

I'll try to baby it more and see if it improves!

Thanks!