Mustang428mach1

I just recently purchased a 2006 F-150 5.4 200k miles keep getting error code P0300 and P0301 only get the codes shortly after I refill fuel when it is sitting at an idle you can feel it miss you can feel the stumble in the motor makes truck slightly Shake entire fuel system was redone before I got the truck but I went ahead and replaced fuel filter any ideas on what it could be

RealQuiet

Could be a bad catalytic converter which can cause too much back pressure through the exhaust manifold which can cause misfires. Had it happen on my 2006 5.4L with 200,000 miles on it.

techrep

iTrader: (1)

Vapor purge valve... read up on it.

BadFish523

P0301 should be indicating a misfire on cylinder #1. Do you know if the plugs have ever been changed? Personally I would start by changing all the boots and springs.

Mustang428mach1

I'm not getting any codes for catalytic converter from O2 sensors no odor from exhaust. Plugs were changed 10000 miles ago

Mustang428mach1

I'm only getting the 2 codes Within two minutes after refilling fuel I can run through a full tank of gas no code I fill up the tank go less than 2 miles code pops up

RealQuiet

Either did I. But after my exhaust blew out I found that the cats were plugged up. Replaced the manifold and cats and never had another misfire.

BadFish523

Well I don't think a gas cap would throw those codes but you could always try to take the cap off then put it back on? I think you just have a simple misfire. Put new boots and springs on your coils and check them out with a multimeter. Here's a video.

You Tube