tripletriple99

First let me give some background info on my car. It's a 1998 Altima with a manual transmission and 174,000 miles on it. Now for the story, I will try to keep it as short as possible. Sometime last spring the car began running erratically when cruising down the highway or through town. By erratically I mean it would skip, buck, lurch, etc. Interestingly though, this would only happen during extended periods of rain. The problem worsened mid-summer, to the point it became difficult to drive the car in the rain. Since the problem began, the service light has only come on 2 times. Both times were in the summer, and both times the car was running so poorly it was not possible to maintain highway speeds. Took it to a dealer to read the codes, which indicated a problem with the mass air flow sensor. But when they tested the MAF it was fine, so they didn't replace it. When the car was running poorly, if you shut it off for 30 minutes, it would run ok for a while. Again, once the weather dried out, the car would run fine. The problem abated for a few months and was far less noticeable during the Fall. But, over the last month or two the problem has returned full-time. Regardless of weather conditions, the car now runs erratically from 10-40mph. If I push in the clutch while this is happening, you can watch the tach flutter around for a few seconds. It never does this if the car is just sitting and you are revving the engine. It also never does this under load, seems to be just when you are giving enough throttle to maintain speed. Once in a while it gets confused at idle and jumps around a bit. Also, it now runs fine at highway speeds of 55mph and above. WHATEVER. I have covered all the basics. Replaced the distributor cap, rotor, plug wires, and spark plugs (looked fine). And, I've fed it about 100 bottles of dry gas over the last 6-9 months. My current thinking is that it's either the MAF or ECM. There is a TSB referencing similar symptoms as a result of A/C evap condensation leaking onto the ECM. I'm going to check the ECM for water damage ASAP. But both of these fixes are expensive so I wanted to consult with people more experienced and knowledgeable than myself. I apologize for writing a book, but I wanted to give you guys as much info as possible. If you need more just ask. Thanks in advance, this has been an incredibly frustrating problem and any help is greatly appreciated.

Ryan

James

I think you should check the wiring to the MAF and the MAF itself. It already gave you the code for it and sometimes a MAF may be ready to die or malfunctioning for a long time before it actually gives up the ghost.

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tripletriple99

OK that's the way I was leaning. But I wasn't sure if the MAF could be screwed up for that long without completely failing. One mechanic told me it probably runs worse in the rain because a faulty MAF is more sensitive to a moisture rich environment. Is this true? And why has it only tripped the service light twice? Judging by the way it runs, I would think the service light would be on all the time. Thanks again.