Drop in MPGs

[Chriskobi]

Hi, new here. I hope this is in the right spot.
I have a 2008 2500 5.7 hemi. I got it over a year ago and recently my mpg went from around 12-13mpg down to 8 or so. I did get new tires and it went down to 10-11ish but that was kind of expected. Changed pvc valve as it was old and did find some oil in air box. Hasn't happens since.
anyo e have this happen to them? Or is 8mpg normal? Truck seems to be running ok.
Chris

 

[xtremewlr]

Check the spark plugs unless you know they were changed recently. And clean the throttle body if you haven't ever done that. Verify the air filter is clean too. Basic stuff but often over looked.

 

[Casper]

Check the spark plugs unless you know they were changed recently. And clean the throttle body if you haven't ever done that. Verify the air filter is clean too. Basic stuff but often over looked.

Do not use throttle body cleaner to clean the TB. Use brake cleaner on a rag.

Plugs (16 of them) are supposed to be changed every 30K miles.

 

[Chriskobi]

I will check and clean.
Thank you for the advise.

 

[Chriskobi]

Thanks for the heads up on the throttle body cleaning and spark plugs. No clue when they were ever changed out.

 

[07MegaCabRam]

The fist thing to note bad plugs is MPG goes south. OR you put in Platinum plugs. Make sure you use factory Champion/NGK COPPER core plugs.

 

[Barricade]

Agree with what everyone said. Basic maintenance e especially cleaning the TB.