Hello,

I have been having off and on problems with a 99 f150 5.4. At first i would have slight hesitation and jerkyness on the freeway when just cruising. Indications were a COP problem. I never had the SES light come on. Then a few months back i had the light come on and the code was for Bank 1 lean. I reset the computer and changed a few dryed out vacume lines and the light never came back but it would still act up from time to time.

Now it came back but this time the stumbbleing and jerkyness is alot worse and it does it all speeds. I could be trying to accelerate to pass and it will be missfiring. The idle is a bit low around 600 to 700 rpm and there is a louder ticking sound coming from the engine. It had another SES light the other day and the code was P0302 missfire #2 cylinder.

I changed the plugs about 2 years ago but it still had a slight stumble back then.
Today i just changed the PCV valve and main hose and fitting to the back of the intake manifold ($50 part at the dealer). Could not find that fitting that goes on the back of the intake manifold anywhere. Also changed a few other vacume hoses that were dry rotted.
Cleaned the MAF with MAF cleaner.
I pulled the #2 COP and swapped it with #1 and reset the computer to see if it moves to #1. I also checked the resistance on both COPS and the #2 was just a little less than the #1 COP, i can't remeber but it was the primary but really not that different in values .55 and .6. The secondary were close. I also picked up a new fuel filter but havent put it on yet. The truck still has a miss and is idleing a bit rough and stummbling. Last night when i drove it home from work it ran pretty good and the tick sound was not as loud.

Any other things i should look at? I have been reading alot of post on the forum and it seems like i have covered alot of the symptons that may be the cause of this except for changing the COP.

Thank you

 

I had troubles with #1 and #2 COP a coulel years ago. Had a small water crossover leak and the antifreeze would geet a few drops dowh around the plugs and short out. When i pulled the COP you could see some dampness around the COP rubber boot and down in the hole.