Any1 ever have there GRP not hold a tune during a race? motor ran fine the first 2 qualifiers and in the 20 min. main the tune was all over the place. one lap it would be fat as heck and then the next would be lean and back-and-forth thru out the race. temp at the end of the race was fine 175Fish, no obvious leakage anywhere on the motor. OS P3, GRP 2053 pipe, nitrotane fuel, motor idles fine, theres really good pinch, and motr has about 3 gallons to the best of my knowledge (bought used). i ran the motor a couple weeks without fault, so I believe it should be something that happen recently. any1 have any suggestions on where to look for the problem first?

there are plenty of places on the track to clear out the motor so i don't know what the deal is...