Hey Guys, I need some I have an 03 F150 witha 4.6 auto 4x4 and only 265 tires. It's now got 83K on the clock and in the past few weeks has started to run like crap. I've recently seafoamed it, plugs have maybe 15K on them as does a new IAC. Fuel filter is new, post seafoam treatment.

My truck is harder to start when the temp is cooler. I've got a slight miss and the engine feels pretty dead in the 35 - 45 mph range. Fuel mileage is actually great, running 16-17 for the past 4 weeks, mostly highway.

I'm assuming the truck's not throwing codes, as I don't have a CEL flashing. Is this true?

Any help is GREATLY appreciated.

Thanks

 

Hard to tell at this point, No cell, no codes will come up from a OB2 scan usually. The delearship can monitor it - 4 a price most of the time .. What kind of plugs did you use?

 

The plugs are Bosch platinums. If I remember correctly they are the double plats, but might just be the singles. No way was I buying those plat 4 things....

Just wondering if there's something else I should be trying to clean or something.

Thanks for the response

 

Descride how it's missing - does it buck at all going into overdrive or at low rpm's while driving? a steady skip, but faint? usually if it's missing you have a coil problem. You said hard to start when cold, that sounds like the plugs. I'm not alone when I say this - Boch Plugs don't work well in my motor and I've read one other post that I can recall that couldn't use Boch. You have alot of miles on your set, so aparently they worked well for this long. Some people have better luck then others using an ulturnit plugs. I've tried the Autolites too, couldn't run those either. I have a 5.4 and an older motor that seems to be picky and likes the OEM Motorcrafts. I would pull a couple out that were easy to get at and see what they look like. Other than that, you might have a coil that's going bad .