I'm new to nitro. I've read all kinds of things on nitro tuning. I still don't have a clear cut answer as to how to tune an engine. Are the pinch test still valid for today's engines. If so, I can successfully perform the idle gap pinch test. However, when doing the 7 second pinch test, where do you pinch the fuel line? How do I know when to stop leaning the hsn? Thanks for any help. If the lsn is too lean, the car will run with a high idle after a high speed pass for a little while. Is that correct? I'm running everything very rich right now until I understand this.