I purchased a 2001 trailblazer. Works great starts up easily, but after about 30 minutes of running will bog down when trying to give full throttle. Cools a little works great. Same thing happens 3 or 4 times when racing around. 2 questions. I think I have a loose vacuum hose between carb and oil injector, could this cause? Should I add an electric fan to keep unit cooler? My friends has same trailblazer but his has an electric fan in frontJust got a 2002 scrambler 90 for my kid and noticed an open vacuum port. Can anyone tell me what this port goes to? It's on the front of the carb.