I have a 1993 Mazda 626 5. Speed manual trans OBD 1, 230,XXX miles 4cyl . I've been having an intermittent yet consistent issue with my mazda for the last couple months. So as a last resort ive decided to create a thread in hopes that someone may have a solution to my problem. The car runs pretty good in dry weather other than an occasional high idle or idle surge but from what I hear that's a pretty common problem with mazda 626s of my generation and the Ford Probes however this does not seem to make the car stall or sputter just idle rough or idle surge. The issue I'm trying to fix is the sputtering and missfire/ and stalling in rainy weather. Note: this issue only occurs in humid and wet conditions. Sometimes after the car warms up to operating temperature it will come out of it, sometimes it doesn't. Ive replace plugs, wires, and the distributor. I have a stock air filter thats has also been replaced. I've tried both w-d 40 and di electric grease on the plug boots but doesn't seem to have any positive effects. Once the weather clears up and the car dries out a bit it seems to run fine again. Are there any electrical competents that could be getting wet and causing this problem? What types of things should I be checking/ replacing. Any info helps at this point I am at wits end with this one.

 

I had a lot of intermittent trouble with my used 626 when i first got it.. eventually turned out to be CRANKSHAFT POSITION SENSOR. Possibly even in the wiring connection. This often gets oil and/or water in it. You can try to fix existing, as it's not "failed". First disassemble and clean on a dry day. Use WD-40 or similar and blow dry or let it dry before reassembly. If that doesn't fix, then try replacing the crankshaft position sensor and it has a wiring connector on the new ones.

I had similar trouble on a GM, after I cleaned the engine, as the sensor is at bottom and water finds it's way in there.