I just bought this and broke it in....All went smooth but about the 6th tank it started coughing, choking on accel and randomly stalling. I replaced the plug and proceeded thru about 6 more tanks of tuning. I got the needle as far out as over 6 turns at one point! Ive also changed plugs twice, checked piston and sleeve for damage (ok), and went back to factory setings (4 on hsn) several times. Im running traxxas 20% and not looking for an amazing racer or basher (nitro helis for that!), just a reliable running ground vehicle. I havnt touched the low needle just yet either. Any help would be appreciated, Tim