This is a Mega Picco ZX .21 version II mounted on a D8. It was a new engine that is having the same problem since new. It runs perfectly only with a new glow plug (hot MC-59 or OS LS3). Once you run 4 to 5 tanks the engine start to flame out when you open the throttle or backfires and dies when I open the throttle. Put a new glowplug and the engine runs again perfectly. Put the old glowplug on another engine and the other engine runs fine. I am talking here of a new engine with a lot of compression and mechanical pinch. I have worked with nitro engines since 2001 and fixed some "difficult" new engines. I am about to give up on this one.

you need to use colder plugs.

And GRP branded if possible..
Type C7

D8? As in Hot Bodies D8 buggy?

Nice detail I've overlooked...
I also see it's a question from 3 weeks ago....
another detail I've overlooked... hahahaha...