Need help with Missing Engine

[Mike Go]

I have a problem with a miss in my 4.0, it has 80,000 miles and when I first start up I'm fine but after I drive and get it warmed up, shut it off for maybe 5 to 10 minutes and start it back up it misses at idle speeds until it fully warms up again but if I run the RPM,s up it dosen't miss. Just at idle speed.
Has anyone got any clues?
Thanks Mike

 

[IAmTodd]

This has nothing to do about your problem, but you title is hilarious. Yes, a missing engine is quite a problem. Ok, I've been laughing too too much lately!!

 

[Alec]

Have the plugs and plug wires ever been changed?

 

[Bill Kemp]

I hear ya IAmTodd, I thought Mike should call 911 & report that.
Mike, have you replaced the spark plugs & wires? With 80K on the meter thats the first place I would start. Motorcraft Double Paltnum plugs and some new wires should do the trick. Personally I have been happy with NAPA or AutoZone wires.



Hay...Alec beat me.

 

[IAmTodd]

Advanced Auto has wires for $30. Had no trouble with them either. I'd agree with sticking to Motorcraft plugs, cheap and all ya need!

 

[Dennis94XLT]

My 1994 Explorer does this too

I have the exact same problem just described. I thought it was the transmission. I've replaced the coil pack, the idle air valve, checked all vacuum lines and even tried premium gas. I have 96k miles on the original plugs and wires. Mine starts fine when cold or if it has been sitting for over 20 minutes, but if I stop for gas - fill it up, make a quick run to the bathroom then come back and start it, the engine shakes like it's misfiring. If I put it in gear and under load, it quickly clears up and runs okay. If I just let it idle and misfire, it will keep doing it for a while. I have new double platinum plugs and will get new ford wires - but I'd like to know if this really sounds like the plugs or the wires. My reasoning is that a spark plug or wire would misfire more under load than just idling and I'd expect it to be worse when cold. Am I wrong? Did the original guy posting about this try new plugs/wires and did it fix it? If so, I'll change mine this weekend. I know it doesn't hurt to change them after being used for as long as mine has, but I've spend a lot of money on other parts that had the same miles and it didn't fix it (like the coil pack).

Dennis

 

[Dennis94XLT]

Mine turned out to be the spark plugs. I changed them and the problem stopped. The plugs were all in good shape but the gap had erroded to be wider than the spec called for.