I have a 2004 GMC Savana extended wheelbase with a high-top conversion. It stalls on me at freeway speeds when it's hot or I'm towing. Temp normally runs just under 200. When ambient temp is around 100 or higher (and when pulling a small 4-wheeler trailer) it acts exactly like an old vehicle would when they vaporlocked. It'll stumble, backfire, and if you pump the gas pedal it might restart before you coast to a stop on the side of the freeway. It hasn't done it if it's not hot outside and/or when pulling a load when it's hot. Fuel filter? If so, where in the heck is it located? Computer just said "lean condition" when plugged in at auto parts store. Already replaced the gas cap and that didn't do anything (previous recommendation). Any help would be appreciated!
