Engine Mechanical problem
2001 Nissan Xterra 6 cyl Four Wheel Drive Automatic 90,000 miles
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I have an intermittent problem with my 2001 XTerra that mechanics have not been able to pinpoint, so far. As with all intermittent problems, it is hard to look at it because most of the time the car runs well.

Around 2 years ago was the first sign, was driving in western NY in a rain storm at highway speeds and the engine started acting erratically. It was losing power and couldn't go over 50 mph, felt like it wasn't firing on all cylinders, but was continuing to run. It had been raining for a few days. When we reached our destination, it sat overnight, the next day with no rain it ran without any problems. And no new instances of this problem.

A year later (last spring) in happened again around my home, again during a heavy rainstorm, which made me realize that this was a symptom (the wetness). But now after the car warmed up sufficiently, it was okay. With this new information, I took in to the dealer and explained the problem, also did some on-line research and thought it might be the distributor cap or some fault in the wiring/plugs. They checked out those areas, ran diagnostics, and could not find any problems, and it didn't act up for them at all.

Three weeks ago driving from Virginia to NY it happened again. This time, however, it was precluded by the speedometer and tachometer giving faulty readings. Both the dials started slowly rising until they were pinned, though the engine was running fine, and then the loss of power started to occur. I pulled over and looked for wet wires or anything obvious, let it sit for a half hour, then resumed the journey. It started out fine, then happened again. Stopped at a service station so they could look at it while it was happening, however they waited too long to get it in the shop and couldn't reproduce the problem (even after driving for 20 minutes), so for $40 told me that the engine was running fine and it wouldn't harm my car, so I continued on.

It kept happening every hour or so, and I would stop and let it dry out. It seemed that the dials were experiencing some rising voltage that would push up the dials, and then sometimes it would reset and become correct again. After the rain stopped, problem went away.

I am about to take it in again but don't think they'll be able to reproduce my problem unless they dunk my car in a lake. I might get the distributor/plugs/wiring replaced or just have them concentrate on that area. Are there other causes I should look into?