I know this topic has been beat to death on some forums, but had no luck searching for it here. Had the same issue again, I did purchase the OEM fuel cap from gm and installed it before heading to car show in saskatoon. When first filled it guages went wacky but after few miles settled in and all was good. On way home different story. filled up at wakaw and put me into limp mode twice, so I finally stuffed rag over cap and everything was happy happy. I am convinced it is all about the fuel cap, but don't know what to do,
