Spark Plug Boot Question

[239]

Hey everyone. I recently got the code P0304 which indicates a misfire in cylinder 4, and I can feel the truck misfiring at start up. It goes away after about 30 seconds when the engine warms up. I had the plugs and wires replaced about 2 years ago and I just noticed that the boot on plug #4 isn’t seated all the way. It must have somehow backed off over time.

Has anyone else encountered this issue? I’m wondering if that’s what’s causing the misfire. I’ve tried to push it onto the plug but it won’t budge. My next step would be to replace the spark plug and wire.

 

[poker4me007]

That looks like # 6 cylinder pictured there. Check the one closest to the front of the engine on the same side.

 

[239]

That looks like # 6 cylinder pictured there. Check the one closest to the front on the same side.

I followed the wire from the coil pack marked 4. I thought the sohc had plug 4 at the front?

 

[koda2000]

Plug/Clyinder #4 is the first one (nearest the front) on the driver's side on either V6, OHV or SOHC.

explorer firing order - Google Search

 

[poker4me007]

Plug/Clyinder #4 is the first one (nearest the front) on the driver's side on either V6, OHV or SOHC.

explorer firing order - Google Search

^^^^^This Plus
O P your sig says ohv and the pic look's like the rear of an ohv drivers side... ohv is the same as in the pic. below.

 

[239]

^^^^^This Plus
O P your sig says ohv and the pic look's like the rear of an ohv drivers side...

Yes, it’s the ohv. I’ll follow the wire again to check.

 

[koda2000]

OHV firing order - same as SOHC

 

[239]

OHV firing order - same as SOHC

Ok I just followed the wire and it makes sense now

 

[Terkins]

I had the plugs and wires replaced about 2 years ago and I just noticed that the boot on plug #4 isn’t seated all the way. It must have somehow backed off over time. I’m wondering if that’s what’s causing the misfire. I’ve tried to push it onto the plug but it won’t budge. My next step would be to replace the spark plug and wire.

Well...it's likely just sitting there next to the spark plug (that's likely corroded over time) isn't helping things function as they could?

I'd try looking inside the (relatively-new) wire boot. If you haven't bent/broken the inner, metal ring by trying to muscle it onto the plug (?), then it should still be "good"? Make sure the tip of the plug isn't damaged/badly-corroded/or-such. Put some di-electric grease inside the plug boot and (with) GENTLE pressure/twisting-PARALLEL to the plug tip might allow the boot to seat correctly (for the first time?)

(My guess) Perhaps the boot was NEVER SEATED FULLY since your plugs/wires were replaced? Road vibrations could easily have unseated the partially-seated boot over time until the misfire eventually occurred.

Just my $0.02.

If the boot isn't damaged/still won't seat: Try "expanding" the inner ring with the opened, single-jaw of a needle-nose plier (slightly). That, plus the di-electric grease, might be just-enough to get it to grab the plug (like it should have been since your repairs.)