2000 f-150 4.6 injector problem

[yorddog]

My 2000 f-150 4.6 that has 110000 miles and is rarely driven anymore(bought a fuel efficient Focus) started misfiring. "Service engine" light came on so i stopped at autozone to read the code. Code was P0301 "misfire cylinder 1". I assumed it was probably the the coil pack or plug, but the problem is now intermittent. I don't have the "service engine" light anymore. Truck runs fine after it is first started but then starts "missing" after a short distance. the misfire clears up after driving a few miles. I heard you can check out the injector with a volt/ohm meter. Any help would be appreciated.

[Rpg0]

Did you replace the COP and the plug ?

[yorddog]

i replaced just the plug. is there a way to test the coil pack with a meter before i replace it? i was also told that if the coil pack was bad, i wouldn't have an intermittent problem. thanks.

[Rpg0]

I too have a 2000 F150 w/a 4.6, I've had the same problems you are experiencing.

The COP's will misfire intermittently when they are going bad before complete failure. I've had #1 only go bad once, but #8 three times since I bought it. I found water to be the cause on # 8 all 3 times. #1 just plain failed. On #8 when I pulled it I pulled the rubber boot off of it I found rust on the spring, so I pulled the plug after I blew out the spark plug area with air and found the plug had rust down the side of it probably causing it to misfire. I had already bought a new COP and plug so I replaced them, problem solved.

I was gonna say you could move the COP and see if the code changes , but you said your not getting any codes now...

[yorddog]

ok. i replaced the COP and had the same result. just so i know i'm right, the #1 cylinder is the first one on the left side of the engine when looking from the radiator, right? if so then i'm back to the injector. i'm wondering if it's not spraying properly and allowing a build up when it cools. after i drive for awhile and the engine is up to temp, it runs fine. anymore ideas before i buy an injector? by the way, i used an ohm meter to check the resitance of the injector and it read 14.4 ohms. i also checked another injector and it too was 14.4 ohms. so i assume electrically the injector is fine. thanks.