glow plug
New to the nitro scene. I had a glow plug killing problem on 2 motors. I used some 4yr old HPI air filter oil and it must not have been any good because i soaked the filters with it the night before i ran it. The motors screamed and ran perfect for about 4 to 5 tanks and boom started eating glowplugs. Brought them home and took them apart to see what i could find and there it was, carb full of dirt. Track was very dusty and i cant drive and spent alot of time on my lid. One motor was a RB S-5 and the other was a O.S V-Spec. Very costly lesson. Now i check my airfilters after every tank of fuel. Might not be your problem but my V-Spec is DEAD and cleaned the RB up and lucky it is fine.