Hey everyone,

Got a question. What would cause my engine to go through spark plugs like candy? Its a 4.0L OHV with 110k miles on it, and I don't beat the truck, but it seems like every 4 months the plug in cylinder 4 begins to misfire, and when I take the plug out, I find the insulator cracked, broken, or completely gone. I've changed the plugs out 4 times in the past year, it's getting annoying and worrisome. Could there be something in cylinder 4, or what else could be wrong?

 

are you getting the right kind?

 

Yeah i am sure, the truck runs great until that cylinder acts up, then i find the broken spark plug. All of the other cylinders are fine, no damaged plugs. It only seems to occur in the 4th cylinder.

 

maybe youve gotten faulty parts what kind do you get?

 

For the spark plugs, I've had Autolite platinum for the past year, but in the most recent change (a month ago) I switched to Bosch Double Platinum, and they seem to work better.

As for engine parts, everything is original.

 

Interesting. I just replaced my plugs in my 1999 truck, new to me. Before I knew what plugs were in there I bought Autolite iridium. The plugs I replaced were also Autolite. I had a misfire on cylinder 4which promted me to install new wires and plugs. My Ranger has only 65K miles. Hmmm.

 

I believe one of these days I'll have to pop that cylinder head off and look in there. One of my friends suggested that there might be a piece of insulator in that cylinder, which is hitting the spark plug and destroying it. Not looking forward to that day....

 

Oh yea, once I replaced the original coil pack all hesitations seemed to go away. Easy four bolt fix.

 

As far as I know, the current coil pack is original. Interesting, I might have to try replacing that, my truck seems a lot more sluggish then back in the old 60k mile days.

 

is your anti freeze low say a gallen every mounth... if so your head is cracked are just need gaskets this is a common problem for the 4.0. i went throught the same thing a few years ago

 

I had the same problem with my last truck, a constant cyl 4 missfire. About 6 month after it started I noticed my water level getting low and after a year of this problem the motor went bye bye on me. It was two thing according to my mech. Broken lower intake manifold gasket and a cracked head gasket. It much cheaper to have it checked and fixed than the alternitive route that I choose.

 

check for a cracked head