Cmiller2

I have an '08 F150 Supercrew with 132K miles on it. The 5.4 triton in it was replaced at 96K miiles because of an injector that hung open and hydrauliced the #3 cylinder which threw a rod out the side of the block.
During the cold winter months the mileage drops off a little but I didn't expect it to drop off to 7 mpg!!!
Is this typical? I am piissed espeically with the gas prices climbing like they have in the past couple of weeks. What do I need to check, fix, adjust, tune?!?!?!
I can tell you that I have an evap system code P0446 currently active. I think it is relate to a bad ground beause occasionally the right signal light will come on and stay on and not cycle which indicates to me I have a ground wiring problem and I know the signal module is good.

trapshooter

Do you have bigger tires? WHat gears do you have?

Cmiller2

The entire truck is in stock form.

Gammel

What gas do you run? Where do you live? High ethanol gas in the winter months will kill your mileage.

MGD

Hi.

Did they inspect the cats and front O2's?

A leaking injector dumps raw fuel downstream and can damage/destroy those components. Typically after a leaky injector fix, R&R of those items is necessary.

At yer mileage yer front O2's are due for replacement anyway - they need to be healthy and responsive to ensure accurate A/F's.

Tire pressures, check disc pads, calipers fer skew/binding, check parking brake fer binding, clean the MAF and TB, short trips = bad mileage, long warmups = bad mileage, exessive idling/stop&go = bad mileage, pull any pending codes, etc, etc ...

good luck

MGD

gone postal

In addition to MGD's list, with the CEL on , it's running in closed loop, which is hurting your gas mileage.

MGD

Hi.

I completely missed the CEL - a most excellent catch, sir!

Yep - that right there will purty much do it, lol. Dang truck will be a dawg, too, causing you to go far deeper into the throttle than usual.


MGD

Cmiller2

When the injector took the motor out, they replaced the motor and the exhaust system along with any othr components that were damaged due to the raw fuel and resultant exhaust system fire.

I live in West-central Wisconsin and we do tend to have gas with 10% ethanol. I have been running the 89 octane because premium here is WAY too expensive to run.

I guess its time to find and fix the problem creating the code to get it out of the close loop state.

I do remeber getting about 10 - 11 mpg with it last winter.

Cutless009

This makes me wonder if my CEL is on but the bulb is burnt out. I recently started noticing the truck feel weaker and my milage went from ~14mpg to ~10mpg.

Cmiller2

Cleared the code and in the first ten miles after I could tell it was running better. Hopefully what ever caused the code and CEL to come on will hold out until warmer weather comes along this spring. I haven't had the turn signal issue in several week s either.