I've read through a lot of the misfire posts. I've got two with problems. Both are E250s. Van 1 is a 97 with 114K on it, code is P0306 (misfire cylinder 6). This plug was damp with unburned gasoline. New plugs and wires and it runs much better but the stumble under load off idle is still there. Check engine light is on and occasionally flashing. I beleive the gaskets were done a couple years back. Does not use water. Should I do compression test, bad valve or something else? Could the coil pack be an issue even though they are supposed to be pretty good?

I have not torn into van 2 yet, a 99 with 140K miles, code is P0303 (misfire cylinder 3) but you don't feel the misfire in it, may just be plugs or wires. These vans are two of the 6 Fords in a delivery fleet so they get hard use and are the lowest mileage in the group. Rest are 4.9 Econolines and one 3.0 Aerostar.

I'd appreciate any help as the 4.2 is new to me and I've already learned a lot reading here.

 

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More work on the 97 van today. I tried a compression test, but the compression gauge would not screw in due to the design of the head. Put a vacuum on it and it was incredibly stead at 18 or 19 at idle.

I looked through the repair history on the van. I had major engine work done at 80K (hard, city delivery miles) and I'm guessing that's why there appears to be no gasket problems. Coil pack was also replaced at about 84K. I'm going to try a new coil pack. If it's not that, I'd guess it would have to be the injector. Any thoughts?

 

Installed a new coil pack. Barely would kick over, you could tell it was out of time. I transfered the wires in the exact same order back over to the old coil pack. Starts fine, runs fine but that cylinder 6 misfire.


What's the deal? I's a GP Sorenson coil pack and I guess it must not have the same firing order as the van (9.7 E250 4.2L). Back to the auto parts store.

Edit: Now I looked at Advance Auto Parts web site. They list a different coil pack part for this 97 van than the 99 van uses. If I look them both up on a Ford dealer parts listing they are the same. Guess there's a problem in Advance's listings.

 

I would have thought the coil pack myself. I just put my 2001 F150 in the shop for missing badly also. They are replacing all the plugs and 4 of the COP's. I called them and they said it's fixed now. Hope this helps.