Misfire
 

Gf was driving My stock 99, and it is hot here. Stopped at drivethru, took off and said it was running bad. She said it was missing. Stopped car for a few minutes ( not long enough to cool down ), restarted and ran fine. No codes...I have spare sensors, but I can not get the damn thing to do it for me. I even have at least one good coil, but I've never had coil trouble on either 99. I am not just gonna swap the parts without knowing which one. Sooner or later it will do it again.:confused:

That is what happen with my 99 when the coil went bad. Once the car got good and hot the car was missing bad. After the car sat for a day untill I could work on it the car ran fine for a short while before missing again.

I would go ahead and replace the coils if you have spares it is easy and does not take but an hour. If it is the coil and it starts failing again the un used gas that gets in the exhaust will ruin your cat quickly.

Just my 2 cents

^^ while this is true...would of had a random missfire code. Should of had one anyway. I think more the cam sensor, although this is more common on 01s and up. It will do it again, and sensors are in the trunk.

I would be careful waiting for the coilpack to go bad. You may have to replace the cat and o2 sensor if you do...

It sounds like a bad cat, there is just no real reason why its the cam sensor. Unless you have been hammering at it or generally abusing it, its not a common fail part for the 99s. Plus, usually a bad cam sensor causes the car to turn off on you also.

As said it is not common on a 99, but they will heatsoak on a 99 also. They don't always turn the car off, but can misfire, buck, or surge. All three of these discriptions, to me sounds like a misfire though. If the cat dies... oh well I'll replace with a spun metalic Magnaflow. The one on my turbocar works great.

they heatsoak, but its not any more than normal (like putting it in the back of the engine).

Either way, seems you have a good grasp of the situation. When the cam sensor gets bad enough it will cut off on you, or if its the coilpack you will just get the misfire & bad cat/ second o2 codes.

It was 106* and setting with AC on..., But thanks. Yep it ain't my first rodeo. Now off to garage to see about slave on Monster, and GFs truck thats overheating.

Been driving this car all week...I can not get it to act up. Might have been just a fluke.

I've still had no luck getting car to act up. I guess its a good thing though. Found a gas leak on Monster @ fuel filter.

cool cool, good to hear. is the fuel filter in the same location as a regular miata? I ask because its an odd place to be looking for anything.