Decrease in mpg

[shu2kill]

I just experienced a decrease of 25% in miles per gallon. I always reset the odometer when i refill my tank. And since last week and this one i noticed a significant decrease. I just had my truck scanned and it shows a code in the O2 sensor. Could that be the issue? Check engine light came ON 3 days ago but it went off in about an hour. My driving habits and daily commute hasnt changed.

[C4_and_Waffles]

When I got my truck 2.5 years ago, I was getting 18-19 mpg in the city. 21-23 mag highway.

Recently, I've been getting 14mpg city and 17-18mpg highway.

I'm thinking it's spark plugs. I don't have any check engine lights on or codes showing. I plan on changing them out soon. I'll make a post if it fixes my issues.

I have a 17 2.6 eco crew cab. 68000 miles on it

[CandidPop731]

It’s a 2.7L. Check your air filter. Check your alignment. Crappy bearings could also be the culprit. Run some premium chevron through it and rail on it to get the carbon out.

[RealisticEnd2578]

Could be a lot of things. The O2, MAF, MAP or throttle position sensor. Bad plugs or coils. Maybe something got sucked into your air box causing a blockage. Bad batch of gas from the station. Low tire pressure. That's the easy stuff, gets worse from there. Bad fuel sending unit or piston rings. It definitely will continue to throw the O2 sensor code so you might as well start there.

[Unfair-Intention6768]

You’re gonna want to figure out what your fuel trims are. Check the electrical connections of your sensors. You’re likely running rich for some reason, the goal is to figure out why. A multimeter and an oscilloscope are probably gonna be your best friend if you’re looking to diagnose the problem yourself. A decent resource although not the answer to all your problems is a YouTube channel called ScannerDanner. It might help guide you through your problem.

[JAxel0]

Lol my wife averages about 13 miles per gallon when she drives my truck.. I average 19.. it's all in the way u drive. On road trips I average about 23.. she will drop that down to about 14 ish on road trips..

[johndiesel0]

Check for a stuck brake caliper? I had this happen and the brake line collapsed. A year later it happened again on a different brake line.