I recently started having intermittent cut-out issues with my 95 miata. I notice this mostly when it is wet and cold outside and almost always just before or after full warm up. Sometimes it is just a stutter and sometimes it will bring the car to a complete halt from 60. I have sanded the corrosion off the 2 grounds I found on the motor (Back and Front) and am still getting the issue. As of late I can flip the car to acc then on and it will generally fire back up(may be coincidence). could it have anything to do with the leaky trunk?

Does anyone have any suggestions?

 

I assume that the engine is in good tune?

I would do a battery load test. Incidentially it should also reveal trouble with the alternator. You could also take the alternator to a parts store for testing.

 

I replaced the battery anter a test revealed it was low and the problem is still there. It is almost like someone is turning off the ECU. I don't get any tach or CEL when it acts up.

 

Does everything else in the car continue to operate properly when the engine is having issues? Try and get a cheap OBD-II scanner that can show live data (they are cheap now, $20-$30 I think), pay attention to when your problems happen and if it is during CLOSED loop or OPEN loop. This can narrow it down considerably.

 

Also: changing the battery is not the same as load testing. When the alternator misbehaves it may cause major variations in voltage. Maybe that is actually turning off the ECU.

 

MazdaTirol, I have an OBD2 scanner however that does not help me because the miata wasn't OBD2 until 1996. I will do the paperclip code scan when I get home.

 

In order to cover the basics I would take the alternator off an have it tested at a parts store. They do that for free. So it only costs time.

 

It appears I got it figured out. The ignition switch had some corrosion internally. A little sand paper and it hasn't done any thing since.

 

Thanks for the feed back.
Nowadays we get so hung up with sensors and stuff we tend to overlook the simple things. But you were already on the right track when you cleaned the grounds.