I just took my 97 down for it's first Smog test. As expected, it failed. I got back two coeds. 1. P0400 Exhaust Gas Recirculation Flow. This is a bad EGR valve and or plumbing. This should be easy enough to fix. 2. P0300 Randome/Multiple Cylinder Misfire Detected. I'm hoping that this is nothing more than bad spark plug's plug wires or coil pack. I'm praying that it is not burned valves or bad piston rings. The car does not smoke at all so this gives me hope. Any ideas on how I can easily narrow this down?

 

So I just spent $200.00 for a new EGR Valve, Plugs, Plug wires and new wiper blades. I had my 16 year old son "help" change the plugs and wires. By help I mean that he did about 90% of the work while i drank a beer and supervised. I showed him how to inspect the plugs for bad singes like excessive oil, corrosion or physical damage and what each of those things might mean. I also taught him how NOT to over tighten the plugs and told him what could happen if they were over tightened. He hopes that one day the Miata will be his lol. I told him he had to help work on it if he wants it some time in the future. When we finished with the plugs and wires, I let him start it up. I told him to goose the throttle a bit. lol He taped the pedal and the engine hit maybe 2k rpm's. I chuckled and told him "you can do better than that!". He floored it right up to 6k before backing off. haha chip off the old block. He then proceeded to do it again and again. I thought I was going to have to drag him out of the car to get him to stop lol. The EGR valve will get done this Thursday when I don't have to work. Only one plug gave me any concern. There was a bit to much fresh oil on it. This came from cylinder one. I will also be doing a compression test on Thursday for cylinder one. If it comes back bad. What should I look at first? The Valves or the Piston Rings? Pleas someone respond to this question. Valves or Piston Rings? They both require a bit of work to get to. But I think perhaps someone with more experience with Miata's will know which is more likely to go bad. Thank You every one.