Hi everyone,

I was wondering if anyone could give me some advice.
I drive an 99 F150, xlt, regular cab, with a 4.6 and 5speed manual transmission. Oakville, built. My Service engine light has come on at least 10 times. Been to the dealer, they claim to have corrected the problem but then it comes on again a few days or a week later. They told me a few times they changed they C02 sensor or something. Once they told me the problem was i should be using different oil! I use the same name brand quakerstate 10w30. I dont think they really now. Anyone know what the real problem could be. The truck seems to be running fine and i enjoy driving it.

Thanks for any suggestions!

 

Welcome stack !!! - Did they tell you that they found any codes when they scanned the system? Did they test your gas cap? If you can't get satisfaction at that dealer, have you considered trying another, or several? Although my owners manual recommends 5W30 oil, I can't imagine why your oil would be causing this. I would find someone with a scanner (friend or for hire) that would let me observe the code results. This will be a good place to start. It is under warranty isn't it? Stay on them and tell us what happens. Good luck.

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2000 F-150 XL,RC,LB,5.4,4R70W,3.55LS,
Class III tow/Payload #3/Convenience pkgs.,
4-wheel disc/ABS,Chestnut/Parchment 40/60,
Ford bedliner & gas/wheel/spare locks,
3" cold air box modification, Superchip,
Dynomax ultra-flow welded 3" cat-back,
3" exit Y-pipe, Hellwig rear anti-sway bar.

 

You really should be using 5W-30 oil, but that's totally another topic that's been discussed fully in other threads.

Have the dealer, or yourself, check all the hoses to and from the fuel tank. Some people have had pinched hoses that caused a problem with the service engine light.

Also have the dealer check the fuel cap. A faulty fuel cap can cause the problem too. BTW, speaking of the fuel cap, I'm assuming you know that the light will come on whenever the cap isn't on tight and the engine is running?

 

Thanks guys for the advice.

 

Have they checked your fuel pressure? My check engine light came on while triving a month ago. When the dealer looked at it, they found that the fuel return valve in the pump assembly had stuck closed. This in turn had caused the fuel regulator to over-regulate and wear out. They found that my fuel pressure was averaging 2 times teh normal level.

Unfortunately I don't think this wasn't the cause of the problem as my check engine light just came on again a couple days ago. So it's back to the dealer with it, and now to find what is causing the my MIL lamp to come on.

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2000 F-150 XLT, Reg Cab/Long Box, Styleside, Oxford White, Dark Graphite Int., 4x4, 4.6L, 3.55 L/S, Off-Road pkg (Skid Plates, Cab Steps, Heavy Duty Shock Absorbers, LT265/70R17SL), Class III Towing pkg with Heavy Duty Cooling pkg, 4 wheel disk ABS, Overhead Console, Factory In-Dash CD, Remote Keyless Entry, and Sliding Rear Window, Cabin Air Filtration, Ventvisors, Ford Bug Deflector, Ford Bedliner.

Currently Forsale: K&N FIPK, Superchip Code: XJB1

2000 Polaris Sportsman 500, Camo Green, 4x4, 499cc 4-stroke, independent suspension, shaft drive, 4 wheel disc brakes, etc.