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Mazda 626 Problem

I have a 1994 Mazda 626 that has never given me any problem until the one I have now. In October of 2007 I was on a highway, coasting at 60, 65 miles an hour when all of a sudden, I felt all power disappear in the car. The tachometer dropped like a rock and the accelerator did nothing. Fortunately, there was no one on the road behind me and I was at an exit and was able to coast halfway off the exit. The car would not restart (dead) and I was towed home. The car was brought by the tower to our repair shop where it started up immediately when one of the mechanics turned the key. They kept it three days and could find no problem. Five months ago I was on a different highway, again on an open road at 60/65 miles an hour with fortunately no one behind me. This time there was no exit in sight and I could only coast over to the shoulder. Again the car was dead. This time, however, I waited five minutes and turned the key. It started up. I turned on my hazard lights and drove to the repair shop. This time they took it very seriously but again could find nothing wrong. Do you have any idea what it could be. I’m afraid to take it on a highway again – I’ve been very lucky so far – and think it might be best to scrap it.

Being intermittent, this is really a tough call. As a best guess, “…I waited five minuets and…it started”, indicates an ignition problem. My best guess is to change the distributor.

This is not a problem that is going to kill you by pitching you off the road, but it is surely not one you want to live with. If you can’t find the problem and want to keep the car, sit down with your mechanics and come up with a list of tests to run the next time it happens. e.g. turn the headlights on and check to see if they came on – That’ll tell you if you are losing all electricity somehow. Keep the list, a pen, and a cheap flashlight in the glove box.

Given your description, it could be either electrical or fuel, but I’m inclined to think electrical. If the engine turns over when the car dies, but the car won’t start and doesn’t even hiccough, I’d suspect maybe the coil or the ignition wiring. If the engine doesn’t turn over, maybe the ignition switch?

If you want to try the hang parts and pray you’ve found the right one approach, maybe replace the ignition switch, ignition wiring, and the coil? Others, may have some better suggestions on what to replace.

The problem might be with the crankshaft position sensor. These things can fail as they heat up and this will cause the engine to shut down. If you wait long enough, the sensor cools down and begins to function and the engine starts. This component can be tested to determine if it’s causing the problem. However, it must be in the failure mode to determine this. What I do when I suspect an intermintant failure of the crank sensor is, measure the resistance of the sensor when it’s cold, and then apply heat to the sensor with a heat gun. If the sensor is faulty, this test will reveal it.

Tester