hey all need some advice, recently bought a arrow straight 04 with 88k miles after the stealer told the owner he needed a new engine or $3500 in repairs. I replaced all parts in accordance with mr. s-vares sticky ( thank you sir) with ford parts. Engine is so quiet you cant hardly hear it running. while driving you can feel that thers something not quite right and im getting a code P0306 #6 missfire. ive switched cop's on #5 and #6 and code returns. I checked the back pressure on the left cat it was less than 2psi, right side appears to be a double overhand bast##d to do. i have a appointment next week with the local muffler shop to discuss options. previous owner drove the truck 3 miles each way to work since new, Also the truck doesnt like overdrive, shutters on hills, as soon as i turn the od off it seems fine. need your advise on this one guys, thanks

 

That's a normal pressure reading in my opinion. I don't know Ford's spec on the 3v, but it's generally accepted that normal back pressure is around 1.5.

Did the code move when you swapped COPs or did it stay on #6?

The truck bucking in OD is from the misfire. It will clear up of you can get rid of it. How bout some service history? Looks like it's about time to change plugs. I'd start there before doing anything further.

 

Start with spark plugs. Especially if moving the COP and having the issue stay on cyl. 6.
There were some issues with leaking injectors in 04/05, but this sounds like classic spark plugs.

 

you guys were right, I didn't suspect a spark plug because the previous owner just had them replaced less than 100 miles ago. but the #6 plug had failed. truck is just great now, unbelievably smooth and quiet. Thanks for the advice

 

did u do phaser work yourself?

 

Yes I did all the timing components myself. Luckily my little woman works at the local ford dealership so I was able to get oem parts really reasonable.