ericantonio

I've been reading that post about mileage and I replied that I consistently get about 11MPG on my tool truck f150 1995. Lent the truck to my ex and got it back and mileage was 22 miles for more than a 1/4 tank, like 1/3 of a tank.

Curious, I filled it up and now I GET about that much on 1/4 tank. I drive like a little old grandma. I've done, this year, since summer, almost a complete tuneup (tps, egr, iac, clean throttle, o2 sensor, cleaned MAF silicon vacuum hoses, ignition coil, dc and wires last year) and all of it helped getting ok mileage. Now for this week, I literally seen it go from Full to 1/4 in just back and forth driving 3 miles out, 3 miles back and down the block to grocery store a few times. Literally 20 miles and I went through a little more than a 1/4 tank.

Here's what happened that could be a problem. I put an efan in (2500 cfm) but for some reason, I was overheating in a hot hot day just sitting idle (90+ weather). So I put that old fan back. But just before that, my coolant leaked from the valve after testing letting it with the efan in the heat to test and waited til my temperature went past halfway. I turned off the engine and coolant overflowed over the cap. That was completely my fault cause I didn't put it in correctly.

Old fan went in and drove for a week and seemed normal mileage but now completely bad. LIke 6 MPG.

Can a coolant leak get into something that could cause low mileage like that when it leaked out? When I overheated, is it possible I broke the temperature sensor? My gauge seems to work okay, on Cool until I start driving and goes to the letter O.

Will a coolant leak ruin my coolant temperature sensor? And can a bad CTS give me bad mileage like that?

Truck is running pretty smooth, idling real nice, good acceleration (I don't drive fast or accelerate fast), no problems really. I did just order new plugs and getting those soon but wanted to see if there is anything else I'm overlooking. Oh, getting a new belt as well but don't see how that could affect mileage. This is just the weirdest thing. I was actually, for a while, enjoying seeing 30-40 miles driven on a 1/4 tank and now not even 20.

fltdriver

Depending on how hot it got you could have fried your head gasket, or it was bad to start with and the overheating just exacerbated the problem.

Pull your codes, check vacuum lines. A vacuum line cracking is a for sure way to cut your mileage in half. Ensure that your tanks aren't cross-filling as well.

ericantonio

Oh boy, sounds like a pretty big job! I searched around this morning and found this:

http://troubleshootmyvehicle.com/for...-head-gasket-1

Looks like I can perform a few tests before I go forward and doing a chemical test.

The engine got hot, but did not overheat. The needle on the gauge didn't get past 3/4 but when it got to needle at half, I cut the engine and coolant did get out of the cap only cause I didn't shut it down correctly.

I don't have smoke coming out exhaust or power problems right now. It's running just fine. I'll check the vacuum lines again. I did last night but in the dark with a flashlight.

ericantonio

On top of it, my knocking seems to be getting worse. Motorcraft plugs coming in today so after a bike ride, will be changed. If possible this weekend, I'll borrow a timing light.

justintendo

knocking?

ericantonio

I think it "knock". Right when I get to about 30MPH and 48MPH, the truck starts to knock or shudder or stutter and I give it a little more gas it stops. I'm not sure if I'm describing it correctly. Knock? Shudder? Bucking? Hesitation? Seems like everything I did to alleviate those kinda help a little when I did it.

ToddS

Just the other day someone was posting about mpg and it turned out the check valve for the rear tank was leaking allowing the front tank to pump fuel into the rear tank. Try and run off just the rear tank for a while and see if that is better.

Truckin

iTrader: (4)

Depending where your at, compliments of the epa, winter blend gas is rolling out. We all lose mpg

ericantonio

That's really interesting!! Come to think of it, I remember reading early start of summer our gas prices here in SoCal went over $3.50 again and it was due to "summer blend, supply demand, Ca emissions are stricker...or (gas companies just wanna make more money...."

ericantonio

I remember that. Right now, I'm only running on the rear cause it's a new fuel pump and new tank. Front tank is original but front pump was replaced early this year. I'll try running just the front.

But I did change the plugs. That was interesting. 3 back ones on passenger side was ...challenging.

Ran *a-little-bit-better*. I get not much of a knocking at around 30mph.

It happens when I'm not accelerating quickly.