Rough Idle - Cylinder 3 Misfire - Just can't figure out the problem - Help!

justynrook

2009 Ford F150 5.4l with 130k miles. Engine had a ticking sound that got progressively louder. Almost like lifter noise. While idling at a light, the engine died and upon restarting sounded awful. It barely ran. After trying to diagnose it a little more I started it one last time. It started up great and sounded perfect. The ticking was completely gone. On the way home it got perfect gas mileage. The next morning I was driving on the interstate and it started lurching.. It threw a P0303 code. When I started it once a bunch of black smoke billowed out of the exhaust pipe. I swapped #2 and #3 coil packs and reset the code, but when I started it back up, the problem remained on cylinder 3. I took out the #3 cylinder spark plug and it looked like it had been hit with something. The porcelain tip was broken and the metal tip was bent. I replaced it, but the problem remained. I put in a new fuel injector. Problem is still there. When I go up a steep hill, it will throw a p0150 code now. Idle is very rough and it doesn't have much power at all. Could a bad O2 sensor cause this problem even though the P0150 code refers to the sensor on the opposite side of the engine!? Could it be the cam phasers? The fact that it actually fixed itself for that little while while I drove it 30 miles home has me completely stumped... Thanks for your help! This problem really has me in a bind. Can't drive to work. Can't go camping. Life's no good when you don't have a truck!

thecardoc3

The P0150 is an O2 sensor bank 2 sensor 1 voltage amplitude problem and would have no direct correlation to a P0303, so the two problems have to be sorted out separately.

Having a cylinder misfire and finding physical damage to the spark plug is not good. Have you tested compression in that cylinder? Do you have a bore scope to let you examine the top of the piston and the valves in the cylinder?

thecardoc3

Guess you don't need that based on the thread from the fix a motor site.

http://fixamotor.com/forum/showthread.php?tid=26

Mr_Shiftright

yikes, that's too bad but when I read about the damaged spark plug I wasn't very optimistic. I figured he either dropped a valve or chunked a piston. At first I was suspicious of the 5.4L cylinder head spark plug threads, but apparently that problem was cleared up by 2008.