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2000 OBW, AT, 290.5k miles when I sold it
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Discussion Starter · #1 · (Edited)
Intermittent miss under light load (solved)

I've got a problem and I wonder if anyone has any suggestions. I have been searching through the forums, and haven't been able to find anything quite the same, so I apologize if this issue has already been beaten to death.

Anyway, 2000 OBW, 225,500 miles. No serious issues until now, and still not enough to make me park it. While driving home yesterday, I all of the sudden had a pretty serious miss while climbing a hill out on the back roads. Flat ground was fine. I had about 15 minutes on back roads, and when I got the highway, it stumbled a little, but was still able to get to speed. After that, it was perfectly fine. 20 minutes later, I went into Walmart for about 20 minutes, came out and the car started doing it again, missing out under light throttle. I was in town, so I didn't try racing it. 10 minutes through town, it was doing it every time I tried to accelerate. Stopped for gas, added some seafoam (didn't really expect anything from it, but figured it couldn't hurt), got on the highway, everything was normal. Headed up some pretty good hills on the back roads to the house, all was good. At home, I looked it all over, tried unplugging and plugging sensors in, rev it up, no changes. Oh, no CEL, idles perfectly. At some point, the A/T temp light flashed. Shut it off, started back up, no more light. Drove to work this morning, doing the same thing for about 10 minutes of back roads. When I got to the highway and pushed it, the CEL flashed a few times, it quickly smoothed out, and took off, CEL went out and was fine the remaining 20 minutes on the interstate. Checked the codes at work, no confirmed codes, no pending codes, nothing.

So, I've not really tried anything yet, I plan to this evening. I'm also going to record the trip home on the AutoTap and see what I can catch. When I was looking at the data stream briefly last night while revving and making it miss out, I noticed nothing unusual. O2 sensors have around 40k (yes, front one is from Subie), NGK platinum plugs have maybe 40k, maybe 50 or 60k on the wires, Belden's I think they are. Also, now that I think about it, maybe 2 or 3 times this summer, and last summer, I'd get a real quick stumble and buck while trying to creep though a parking lot with the A/C on. I always wrote it off as the IAC not compensating for the extra load from the compressor quite right. It was always just a few seconds, and only while just barely on the accelerator. Oh, and the throttle body is clean as well. I have had a P0420 for a year or so now, I just keep turning it off, because I'm not about to spend money for a new cat for a car with this many miles.

Anyway, any ideas would be appreciated. Thanks!
 

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2000 OBW, AT, 290.5k miles when I sold it
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61 Posts
Discussion Starter · #2 ·
Huh, I'm kinda surprised I didn't get a single idea! Oh well, it's fixed now. It missed out the entire drive home Friday, the CEL flashing now every time. Still no codes. When I got home, I pulled the #3 plug wire, and there it was, a gray burnt spot on the boot, around a small hole in the rubber, and a matching black spot in the plug tube. I popped one of my old plug wires in there, ran perfect. Took a 500 mile trip to OH Saturday, ran beautifully. And the wife thinks I am crazy for saving old parts!

So, what really threw me off was the CEL. Last time I had a bad misfire, I got misfire codes for all but one cylinder. I had no codes this time. And I didn't realize that the flashing CEL actually meant misfire. Who knew the owners manual could actually have some helpful info?! Oh well, all is good, and I didn't have to spend any money trying things that didn't work. Plus, the wires I had bought before have a Napa lifetime warranty, so I'll get them swapped out here soon. I did notice I have a little oil leaking into the #4 plug tube, so I'll get those gaskets changed out. I need to get in there and do a valve adjustment anyways.
 

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I missed your first post, but glad to learn that it's now resolved.

Surprised that there wasn't a "pending" code after the CEL flashing. I though that would be the case, as it was with my 07. Perhaps it's different with the 2000.

Sure you want to go with those same wires, even with the lifetime warranty? (How old are the NAPA's?)
 

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2000 OBW, AT, 290.5k miles when I sold it
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61 Posts
Discussion Starter · #4 ·
Yeah, I know, if it had thrown a #3 misfire code, I probably would have found it much sooner! I also would have expected it to me more constant, like it was going home Friday, instead of being intermittent and running perfectly fine at times like it was before. Oh well, live and learn I guess. I even hooked up the scanner and went out and made it misfire, just to make sure nothing popped up while the CEL was flashing. Nothing.

Yes, I'll stick with these Napa wires. I don't mind changing them every 50 or 60k as long as they're free! I'll just keep one or two of my old ones and a roll of electrical tape under the trunk in case they break down on a trip. :29:
 
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