greenf1502007

I bought the truck about two months ago an it's been having problems. It has the 4.6L with 73k miles. I bought it at 69k. First problem was the truck idles rough and the CEL came on. This was a month after i got the truck. The dealership checked it out an replaced the throttle body under warranty. This helped... Until now.

Now the truck shudders really rough, and when I pop the hood, you can see the hood shaking. The check engine light also came on. Today, I decided to disconnect the negative terminal because I thought maybe the dealer didn't do it after they replaced the throttle body. When I tried to start it up again, it shuddered and didn't start. I let it crank for 3 seconds then just turned it off because I was scared to mess the engine up. Any ideas on what happened? Vacuum leak possibly?

metallic08

did the truck have it's 60k mile tune up? check the air filter, fuel filter, and vacuum hoses.. and possibly have an injector malfunction or COP going bad...

greenf1502007

I have no idea of the tune-up has been done. What all goes into the 60k mile tuneup and how much does it cost? I'm guessing the extended warranty doesn't cover it...

04xlf150

I did mine myself and it cost 13 bucks for a fuel filter which was easy to install if you have the right tool for it. I don't really know the name of the tool but it looks like scissors with a circle at the end to disconnect the fuel lines. And I have a non disposable k and n air filter so it cost 13 bucks for the cleaner kit. After I replaced the fuel filter it made my truck run a heck of a lot better! The gas that came out of it was dark brown! I replaced it at 74,000 miles and the previous owner def didn't replace it before so that could help. All my hoses were good though so I have no clue on how much those are either. To check the hoses you basically just inspect them really well and make sure there's not any cracks or dry rotting. Hope ya can figure out what's wrong with it!

metallic08

is your check engine light on?

greenf1502007

Yeah it's on

greenf1502007

Thanks, I'll try that. And I rode my friend's 4.6L yesterday with only 50k miles and I was so surprised at how smooth it ran and idled... I'm so jealous!

metallic08

run a obdII code scanner to check why your lights on and that might solve your problem.. might have an oxygen sensor out..

greenf1502007

Update: went to the dealership to get a tune up and it's a lot smoother now. Not as good as my friend's f150, but its more responsive and overall rides better. They changed the spark plugs and hanged the fluids etc. for $300

St.Somewhere

Same problem, but my rough idle comes and goes and no check engine light on. All the sevice is up to date also. Mine started to idle rough today and i put it in neutral and reved the engine and it smoothed out afterwards.Truck runs great and has plenty of power and good fuel mileage. Any advice anyone can give would greatly be appreceited. The last thing i want to do is nickle and dime my bank account..