I have a 97 Explorer V8 with AWD and recently started to experience terrible gas mileage in the last two months. Averaging 14 mpg on the highway. I've owned it for about 18 months now and had averaged 23 mpg on the highway and 15 in the city until recently.
Ran a diagnostic check and came up with no errors or codes. What gives?
-New 02 sensors (all 4) about 8 months ago
-Catback exhaust Flowmaster 70 series 8 months ago
-MAC Cold air intake- 8 months ago
-New plugs 8 months ago
-Religiously change oil every 5000 miles with Mobil 1 synthetic oil
-Tranny oil flushed 8 months ago

I have no idea what the deal is here. Any insight would be greatly appreciated

 

How Recently have you Changed your Air Filter? Also Check your Tire Pressure.

David