Stumped and Frustrated with a Holley 670 Hesitation

[ame="http://www.amazon.com/AEM-30-4110-UEGO-Ratio-Gauge/dp/B00N3VGPYS#productDetails"]Amazon.com: AEM (30-4110) UEGO Air/Fuel Ratio Gauge: Automotive[/ame]

That one is pretty good. I think it will allow for logging as well. It's good to get the readings along with rpm.

If the check ball from the bowl to the pump diaphram is messed up, that might cause a delay in delivery. Sometimes it's a rubber style plug.