Jason Johnson

hello new to the forum here, ive just done plugs in my f150 5.4 3v 2004 and i was driving home and the truck threw a blinking check engine light ( luckily i had the scan tool in the truck right next to me! ) i pulled over quick and scanned it and it pulled up codes p0305 miss fire #5 p0316 miss fire on start up after first 1000 rpm and p0174 for drivers side bank too lean witch is where cal #5 is located.. this skip was really bad when it happened i actually got nervous.. i had already replaced #5 plug twice the same night and the problem went away after doing so then came back obviously on the ride home... I'm kinda stumped as to what my issue is, im thinking maybe a bad or clogged injector or a vacuum leak but the truck had a bit of a rough idle before hand hence why i was changing plugs. but it didnt fix the issue only got worse, helpp !!

RLXXI

Sounds like you put Autolite spark plugs in when you should have used Motorcraft but I'm just speculating.

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Jason Johnson

I did use autolight plugs but i swapped #5 out with one if the good motorcraft ones that i took out i even put the plug in the coil and grounded it out to check for spark and it was fine, this is the second time with 2 difrent brands what keeps killing them off ?

Jason Johnson

I also checked for spark and fuel i have both and still have a skip.

techrep

iTrader: (1)

Swap COP's for another cylinder and see if the mis-fire code follows it..

Jason Johnson

i did that but it didnt work. i did however solve the issue. i disconnected the battery and touched the positive and negative connections together and erased all memory it straightened the skip right out. i do however still have a bit of a rough idle not a dead miss but almost as if its a bad IAC.. i pulled maf sensor seams to be clean blew it out softly. didnt correct it ..