First Time...

I downloaded an app Track Addict and went out to a relatively flat long straight road. the road runs almost due east. The app came back with 26.35 s at 70.2 mph for 1/4 mile. I don't know how accurate the app is? The 1 to 2 shift was about 40 mph and the 2-3 shift was just under 70. I had a stumble at about 50 mph (I think it is a fuel starvation due to fuel heat vapor lock issue like i have at hot idle) but it cleared its self. on the return run same road opposite direction at about 50 the engine kicked and bucked and I let off the gas and it recovered but wasn't happy after that.