98 Explorer 5.0 Engine Miss/Stumble

[jr1017]

Long story as short as I can make it. 1998 5.0L, stumble on acceleration/load. Had codes checked at autozone, cam position sensor and misfire codes came up. Took to mechanic and $380 later, had it replaced, he showed me old one and it was really bad. Magnet had broken and fallen down and twisted up other things. Anyway, seemed to run much better, check engine light off but still some missing. He suggested tune up as well, still had original Ford plug wires on. Within 2 weeks check engine light came back on and missing under load. Mechanic wanted $275 for tune up, which seemed kinda high but maybe worth it, and after doing it myself, seems like a really big rip off because it really wasn't that bad of a job. Weekend one, replaced 4 plugs and wires. 2 on each side. Plugs were Autolite, so they had to have been changed at least once before. Plugs looked fairly crusty and kinda burnt, so glad to have them replaced. I used Champion platnum, not sure if that was the best choice or not. I heard someone say once to use double platnum, but these were not. Also did not check the gap, just put the new ones in. Ran flawlessly and so nice for a few days, then started acting up again. Weekend two, replaced the other 2 plugs and wires on the drivers side of engine and 1 on the passenger side engine. Cant get my socket around the plug with the heat shield around the plug so still need to work at that. After replacing the other 3, once again, it ran really nice for a couple days, then its doing it all over again. Bad miss like symptom. At idle, under load (accelerating between 30 and 60) a/c running. Sometimes it runs bad, then turn off the engine and go into a store or something, 30 minutes later start up to leave and it runs much better, still there, but not nearly as bad. What could be causing this sort of thing. Maybe I missed it during my search, I don't think its just from the 1 plug and wire that I have not changed yet. What area should I look into next and sorry this is so long. Am going to finish the other plug and wire this weekend and whatever else I can think of hopefully with some advice from you guys.

Thanks

 

[marragtop]

Consider cleaning or replacing the IAC. Have you replaced the fuel filter? Also check the PCV valve.

 

[Dilbert5]

I strongly recomend gapping the plugs before installing. It does make a big difference, some engines are even more sensitive to this than others. But it is definately time well spent.

 

[marragtop]

Also, the plugs are easiest to get to thru the wheel wells.

 

[celly]

Give your engine a good Seafoam treatment. Try the PCV method of applying it. It's trickier than the brake booster method, but does a much better job. It can't hurt and may solve your problem. Cleaning the MAF is an easy thing to do as well.

Lots of good info on the site on how to do both. The Search tool will bring you several threads on both topics.

 

[jr1017]

Thanks for the input, picked up fuel filter and will add that to the list for this weekend. Will also try either seafoam or some other injector cleaner along with the last plug and wire. The wheel wells seemed to be the only way to go on this. To be continued...