I was inspecting my plugs today, and the leadings are beautiful, nice brown clean color, when i took out the trailings i was a bit shocked, they were covered with a thick black film. This is the first time i have looked at the plugs since i installed DLIDFIS and at that time they were brand new plugs, about 11/2 months ago. reciently i have experience harder cold starts, and a slight stumble. My tach works fine, and seems to be getting spark. Whats going on?

matt

 

Could be a number of things
1) too cold a plug - and mazda actually recommends a colder plug in the trail which I found to be too cold to the point that the plugs were not hot enough to burn off deposits ) - I run 8's rather than 9's. This would be my first guess because I had the same problem until I switched to the 8's

2) Running Too rich - Carb or FI? If you have an SE, check the mixture screw (which, BTW, only impacts the mixture at idle) - best way to foul a plug is to run rich at idle

3) Timing - make sure you are not running retarded on trailing

4) Too much putting around town - rev that thing!