'99 Inttrigue 3.8 misfire

[cokemanj]

First a little background. I have a 1999 Intrigue with 126xxx miles on the 3.8 engine. About 1.5-2 years ago, my Intrigue began having trouble starting and randomly shutting off while driving. Soon around then, it also started sputtering while entering the freeway between 50-60 mph. I brought it in to have it checked and was told it was most likely the ignition switch. Being fresh out of college, I didn't have the $300+ to fix it. So I drove it as is and dealt with the problems. I had enough reason to believe that the sputtering was also due to the ignition switch. Finally, last month I got the ignition switch fixed. The starting and killing problems were fixed, but the sputtering still remained. That weekend I bought some new spark plug wires (I had replaced the plugs themselves a couple years ago but nobody in 20 miles had wires that day so I skipped them) and put them on. Problem solved! No hesitation at all. It was like when I bought the car, it felt like new to me again.

Unfortunately, after ~100 miles it started sputtering again. Just a little at first but slowly degrading back to how it was before. What could be the problem? I bought the cheap set of wires from Autozone, might that be my problem? I know driving with a misfire for nearly 2 years can't be good, did that do something? If so, why did it work perfect for about a week? I only got the check engine light to come on once (vs. ever few days/week before) but I haven't checked it yet. Last time I checked was cylinder 3 misfire. What should I do to try and fix this problem? Thanks in advance for your help.

[LittleHoov]

Is the check engine light still on? if so get the codes.

If the misfire is on cylinder number 3, I would check that one, i believe that is the one on the front in the middle, but i cant recall. If your coils are numbered all you have to do is trace the wire to that cylinder.

A bad coil pack is a possibility, to rule that out you can swap the coils around and see if your misfire code switches cylinders.

[cokemanj]

No, the light is not still on but if I remember correctly the code should still be active. I will try and get it checked this weekend. If the coils are bad, would it still have worked perfectly for that one week? Is it that the bad coils burned out my new wires? It sounds like you’re saying that coils are easy to switch, would that mean that it would be a relatively easy fix if that is the problem?

[LittleHoov]

Yes if you can narrow it down to a bad coil they are relatively easy to fix.

There are 3 coils on the left side of your engine, each controls firing for two cylinders, but at the same time that doesnt explain why its working fine now.

The ignition system will usually start acting up under high load at low rpms, so if you find a good sized hill to chug up in 4th gear or something like that it might start acting up again, perhaps enough to throw another code. I also dont believe you can retrieve SES codes once theyve been cleared by a machine.

[cokemanj]

Ok, I finally was able to switch around the coil packs. Here’s what I did. I checked the code and got cylinder 2 misfire. I cleared the code and then I switched the coil pack with cylinder 2 with another (one containing cylinder 4). Drove the car up to the parts store and was able to get it to throw a new code as soon as I hit the gas on turning on to the main road. Checked the code and got another cylinder 2 misfire. At this point, I thought that maybe one of my new cables was faulty, so I switched the cable going to cylinder 2 with the one going to cylinder 4. I had hoped to get a code for cylinder 4 but ever since then (Friday) it has run fine, no sputtering at all!

I expect that the sputtering will re-appear in about a week like last time, so what could be causing all this? I’m pretty sure the cables were connected fine when I replaced them as we made sure to double check each one so I don’t really think it would have been that. Could it still be the coil pack? Would it be something between the ignition and the coil packs? Additionally, when I last checked the code on this in October (before fixing the ignition switch) it was cylinder 3 causing the misfire. If the sputtering doesn’t come back then great but if it does, what should be my next recourse?