I'm hoping someone can help me. At a race last weekend, my GRP tuned .21 engine in my buggy completely died. Both I and everyone else thought it was the glow plug because it would run on the starter box with the plug heater on it, but then it would die once I took it off. I replaced the plug with a new one 3 different times (P3 and tried a P4), but it kept dying once I took the heater off.(I'm in Florida, so the outside temp isn't an issue) The engine only has about 3 1/2 gallons through it, ran very strong and has plenty of pinch left.

Can anyone give me any advice as to why this is happening and suggest a fix? I appreciate any help I can get!