Gas Mileage Has Gone Down

[bw4sale]

My Dad has an '02 1500 with the smaller V8 and about 90k miles on it. In the past 6 weeks his gas mileage has dropped significantly. He's now averaging around 13 mpg. He was going to do all the basic maintenance things, plugs, wires, filters, etc. Any thoughts on what might be causing this and what he should do?

[67ChevyRedneck]

Have the plugs and wires ever been changed?

Is he letting it warm up for 5+ minutes before leaving everyday? Winter idling will kill a mpg or two over a tank. Mine usually drops a mpg or two in the winter as well. If he's doing mostly city-ish driving, 13-14mpg is normal with E10 in the winter.

[bw4sale]

No, the plugs have never been changed before.

[69gmcc10]

Did you recently change fuel stations or does your fuel change in the winter time? Ethanol in the fuel will decrease your mileage! In the summer here I need to watch out for stations that have 10% ethanol fuels, because some stations have it and some dont. In the winter every station here sells 10% ethanol so I can kiss at least 2 mpg good bye until spring.

You may also want to swap out plugs, clean your mass air flow sensor, change your fuel/air filters and run some injector cleaner through the truck if it has not been done recently to see if it makes a difference.

[Special-Ed]

fuel will do it every time... the more ethanol, the less mileage...
i bet they went from a summer blend to a winter blend...

if its an '02 with original wires and plugs.. they are shot!