03 Grand Caravan, 3.3, Lousy MPG

[mixbrix]

Lately it's been getting 11 and 12 MPG. New plugs installed 20,000 miles ago, regularly change the air filter, change oil and filter every 3000 miles or less. Check engine light came on, Autozone checked it and said it was the fuel cap. Replaced cap and light has stayed out. I was thinking maybe the fuel filter, but I think I read somewhere it's an electric filter in the tank??? Was told maybe it was a vacuum leak, so I sprayed carb cleaner around all the vacuum lines and idle didn't speed up (or is that an old wives tale?). Only other thing I'm thinking is the catalytic converter, could a bad converter affect the fuel milage?

[RIP]

Was this a slow degrade to 11mpg or did it happen over night? Any maintenance done just prior to this? Using E85 ethenol?

The filter isn't "electrical". It is mounted on top of the fuel tank. You have to lower the tank to get at it. That said, it's doubtful the filter is the culprit. It's designed to last the life of the van. Plus, if it were clogged you'd be seeing driveability problems. Are you? Is the check engine light on?

[mixbrix]

[quote=RIP;6925625]Was this a slow degrade to 11mpg or did it happen over night? Any maintenance done just prior to this? Using E85 ethenol?

It was slow. I think when we first bought it it was getting 19 around town. Have never used E85 in it and hasn't had any maintenance other than what I had stated. Fuel filter sounds weird, I guess I'll stay away from that.

[b1lk1]

CHeck the free stuff first. Make sure none of the brakes are binding. Make sure hte air filter is clean. Ask yourself if you have been driving aggressively as of late. Don't rely on the MPG calculator on the readout, do the math manually as well.

[mixbrix]

Originally Posted by b1lk1

CHeck the free stuff first. Make sure none of the brakes are binding. Make sure hte air filter is clean. Ask yourself if you have been driving aggressively as of late. Don't rely on the MPG calculator on the readout, do the math manually as well.

All brakes are new, and I think the air filter is fairly new, but I'll check it tomorrow. I found out early the MPG readout isn't accurate. I always check it and it's usually lower than the readout says. We have a trip planned in November from Florida to New Jersey and I'm hoping the MPG improves by then!

[stlrj]

Originally Posted by b1lk1

CHeck the free stuff first. Make sure none of the brakes are binding.

Jack up the rear and spin the wheels by hand to see if the brake shoes have fully released and are not binding. They should freewheel with virtually little noticeable resistance.