What would cause this? Driving downhill it acts like the fuel pressure is going up and down. Goes RICH (100BLM) back to 128, then back down, surging. going uphill it just stays at 124-128ish BLM... With roughly 10 gallons in the tank, it idles fine, but then as soon as I fill it up, it's back overly rich again. Could this be because of a bad regulator? Obviously it's impossible to get tuned correctly like this.