My 2005 5.4L Supercrew F150 had its check engine light come on. I got the code read and it was P0300. The most common thing is your gas cap is off or loose. I had them clear it out and let it go. It came back on a few days later and I thought nothing of it.

Lately it has had problems starting in the warmer parts of the day. Sometimes it cranks awhile and then starts. Other times it barely cranks at all and starts with low RPMs and is a little rough at first. I have no problems with it after the start except my gas mileage is suffering.

I went back to see if any other codes had come up. Now I have the P0300 code and P0442 which is a random misfire.

I have had suggestions from a tune-up, temperature sensor, and a faulty coil.

Anybody had similar problems or think they may know what is wrong?

Thanks

 

Sounds like a fuel delivery problem. Add fuel filter to the tune up list.

 

Thanks, I took it in yesterday and so far they have found that cylinder 5 is misfiring but that is the only one. That seems a little odd that I had the random misfire code instead of the one for just cylinder 5. I will look into the fuel filter thing as well.

 

Was your gas cap actually loose?

 

BTW, you have your DTCs reversed. P0442 is the evap control leak, which is frequently caused by leaving the fuel filler cap loose. P0300 is random missfire.

When you say
do you mean that it cranks slowly? Or do you mean it starts immediately?

 

starts immediately but its real rough and takes awhile for the RPM's get up to where they normally should be at start up.

 

No, but I did have the shop look into this one as well. Check the seal and the lines, etc. They do not seem to think that whatever is throwing the two codes are related.

 

just look at your pcv hose and make sure its not sucked shut or rotted.

 

P0442 is a small evap leak detected code. Gas caps very rarely set small leak codes, they usually cause gross leaks (P0455) or their own dedicated code that says "gas cap loose" (P0457).

As for your P0300, start checking things that are common to all cylinders. A misfire on one cylinder could cause a multiple random miss code, yeah, but I'd also check fuel pressure, volume and quality.

And being that your truck is an '05 5.4 3V, it probably has a/an injector(s) sticking at times.

 

X2 Quinton kicks a@@. Probably a bad injector - 05's have an issue w/ bad injectors - and Ford will cover it under a new extended warranty issued by Ford for that specific issue.

Have you had an odor of gasoline or any signs of it running rich?