P0304 - Cylinder 4 Missing

[charsawbis]

Need help.
Been having engine issues. Bought a code reader and cylinder is missing. Check engine light keeps coming back on. I replaced the DPFE and it got a bit better. Now it runs better when warmed up, but still no good. Cant accelerate hard.
any ideas as to what could be wrong? I suspect a vacuum leak.

Going to seafoam this weekend. Need to replace the PCV valve as well. Anyone know how to find it. I been looking and cant locate it. its a 1996 4.0.

Any help is much appreciated.

 

[rwenzing]

4.0 OHV engines are notorious for gasket leaks where the lower intake meets the heads. A miss on #4 is often caused by a small amount of coolant leaking into the #4 port.

 

[charsawbis]

crap

that sucks. i was hoping it would be a vacuum leak. i'm going to grab a new PCV hose and valve assembly from Ford in a bit. Hopefully that will help a little. Will dumping some stop leak into the coolant help? I basically need a quick fix untill i have time to address the issue properly.

 

[manaen]

what does the plug look like on that cylinder?

 

[charsawbis]

I haven't dug it out yet. i will go mess with the wires and check the connections. can i swap the coil packs on a 4.0? i read about that in another post but it was related to a 5.0 i think.
How hard is it to get to plug #4? i know some require tools or double jointed appendages.

V

 

[manaen]

Well the find the miss I would start with the simple things.
1) plugs & wires
2) check coilpack (use multimeter)
3) vacuum leaks
4) be sure to use dielectric grease on all electrical connections


Then move to the bigger things
1) check fuel injector (maybe swap it with another cylinder to see if the problem follows). Also be sure to check and replace the oring seals to make sure they are not leaking.
2) gasket problems etc...