Stock ignition
NGK-BKR7E's
RC 440cc's
Walbro 255
My car just started missing about a week or so ago. Nothing has changed in the setup or tuning. It's very random though. I drove to school the other day, and it was fine. Then on the way home, it was missing a lot. It usually goes away in a few seconds, or just misses a couple of times.

I pulled the plugs and they look fine. Normal looking, and they are all the same color. I havent messed too much with the other ignition components, but I'm actually not convinced that it's the ignition.

Just recently, when it's missed, it sounded like it detonated just a little bit. If that's the case, I wonder if maybe my fuel pump is dying. It's been making some weird noises lately. Not always the same tone, or loudness. Sometimes it whines a lot, other times, not as much. Battery is brand new.

Anyone have any other ideas?

 

Do you have a chipped ECU?

 

when your pump is making this noise. pull the fuel line off the rail and put it in a bucket then turn your key on and observe the flow. make sure it is a steady stream.

 

Yeah, it's a chipped ECU. How would that affect my miss?

I'm running Uberdata 1.70 btw. Soon to upgrade to Chrome.

 

Well, I figured out what it was. It wasnt anything with the fuel system.

The little phillips screw that holds the rotor on inside of the distributor came out, and was just rattleing around inside of the cap. My guess is that when it started missing, that screw was interrupting with the electrodes inside the cap.