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Please forgive me if I'm posting this in the wrong place, it's only my second thread, if I am improperly posting hopefully an admin can move it or delete it for me.
Anyways here is my issue. My truck has been misfiring since I bought the thing back in May on cylinders 2 and 6. Naturally it seems like spark plugs are a good place to start, especially since I have no idea if the previous owner has changed them out. So I buy 6 plugs and 6 spark plug wires and spend a morning before work changing them out, I get 3 plugs in and the next 3 won't budge at all, I don't force them because I don't want to break them. I simply change out all the wires and get ready for work. 2 of the 3 plugs that wouldn't budge are the ones that misfire. When I get ready to leave for work I start the truck and sure enough it's still misfiring, but when I get on the road I notice it sounds worse than before and the acceleration doesn't feel right. I get home to make sure all the wires match up with the correct firing order, and that all the boots are on tight and properly. It still runs poorly.
So at this point I google what could be the problem, and I realize that perhaps the gapping on the plugs could be off. They're supposed to be pre-gapped but apparently that doesn't always mean they are. So I decide to put the old plugs back in. After all these 3 plugs weren't misfiring and they should still be gapped correctly right? So I do that and it still sounds worse than before.
At this point I'm lost, I don't know what to do with or what I did wrong that would make the engine perform worse now.
So I have to ask what could I have done wrong with changing the plugs out that would cause the engine to perform worse than before?
How can you be lost ? Change ALL the plugs. Just because the plugs are a little tight doesn't mean you should leave them in and forget about it lol. Break them loose while the engine is warm if you have to. You most likley have compounded problems by now. The cats have to be wasted. You fail to mention the spark plugs your using as well. If you want to keep that to yourself so be it, but we can't help without details.
For the plugs that are stuck. It's not necessarily an issue of I don't want to remove them, I simply didn't have enough time this morning or yesterday to remove them before work, and I didn't want to risk breaking them. The plugs are auto lites, the old ones are and so are the new ones. It's not like I did half the plugs then just gave up on it. Aside from the misfiring from before the truck has ran perfectly fine, and now it sounds terrible. I didn't cross any wires, I've since made sure they are all gapped properly, and I didn't have any boots loose. I'm not lost with what to do with all the plugs I'm lost when it comes to what I may have done wrong to make it run worse than before. I would like to think that the issue isn't due the fact that I didn't switch out those 3 plugs.
I see, yea Autolites aren't a Ford plug (although they still cross as OEM replacements, they are not)... Motorcrafts are. The Autolite is the second worse plug you could install into these engines. A certain Bosch plug series are the worst. Use the owners manual to set you straight on proper maintenance and replacement parts. This can be critical, specially with plugs and PCV valves.
Unless theres other problems, a fresh set of Motorcraft plugs should help quite a bit. Yea , even new Autolites can misfire right out of the box.
12-30-2016, 11:54 AM
Spark Plug problems on a 1997 4.2L
