thats about the time the secondary opens up. is the secondary plate free? the way to check the secondary without driving the truck, is take a rag and restrict the primary while revving the engine. the secondary will open and the engine still run. restricting the primary is to keep the engine from over speeding. hold the engine about 2500-3000 cup the rag over the primary and increase the rpm. if the secondary is working it will continue to run. caution!!! don't do this very long. you should be able to tell fairly quickly
Thankx tried what U said and the secondary works.
I think I might end up doin' what I did on my 82 Datsun and put a 350cfm Holley on it and be done wid it.
