Ok about a month ago I posted tha t my truck ran like sh*t.I got the o2 sensor fixed and changed the oil and spark plugs.Ran great for about two days.Now it's back to about nine miles per gallon.I do have 90,000 on my f 150 4x4.Now on the way home my dash lights went out on my gas/temp gauge.Any help is appreciated.

 

Judd10,

Do your guages still work? If so, sounds like burnt bulb in dash. As for the 9mpg...
Some thing might be killing your O2 sensors.
Do you use fuel additives? Do you use brand name fuel? Again, what engine & tranny?

Regards

Jean Marc Chartier

 

My truck is a 1997 f 150 4x4 4.6 liter with 90,000miles. I have been running this truck the last 30,000 miles with the check engine light on because of the 0 2 sensor. Got it fixed and complete tune up. Thought it was a new truck the next day.But now it is back to normal only missing the check engine light.As for the dash lights it's only the gas/temp gauge lights.

 

30,000 miles before you got it fixed? Ouch!
A bad O2 sensor can make your truck run rich which in turn burns more gas, carbons up EGR system, has more volitile gasses running into cats, which can clog those up, causing back pressure or cat meltdown. Lots of possible reasons for 9 mpg. I would start with an emmisions system cleaning/de-carbonizing and go from there. Letting things go can cost more in the long run than if you just changed out the O2 sensors.
(Jeez I'm starting to sound like my Dad!)

Check the PCV valve too, if thats really carboned up you know thats probably the problem.

Hobbit

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99 XLT,4.6L Auto,4X4,tow pkge,Factory Side Steps and Mudflaps, K&N filter,BugflectorII, Amazon Green/Silver, Pace Edwards Rolltop Cover.