Jerry,
Interestingly enough now that you mention it the economy does not seem to change appreciably between winter blend and summer blend and even factoring in foothills and traffic when you are putting in 20+ gallons of gas every 175 miles, give or take, there is a problem somewhere. I have been driving these roads since 92 with a variety of vehicles and this is the first one that is this thirsty. There is fuel economy in these engines somewhere, if I am not mistaken the hot rod Corvette gets good enough mileage that it is not subject to the gas guzzler tax. Granted there is little comparison between the Corvette and my truck but it is still a gen 3 small block.

Cleaning the injectors can't hurt. I supervised an LAPD repair shop in the 90's, I rarely did any work on the cars but as I recall it is just a matter of attaching a device to the fuel line and screwing a can of cleaner to it. Any idea if any of the chain parts stores rent the equipment?

As for dyno tuning ask Corey about the E3 plugs, do they really live up to the hype or is it just advertising smoke? Also what about an aftermarket tuner, can I tweak and peak the timing and mixture with one of these. While I am not totally opposed to pulling the engine and playing around with camming and heads it is not at the top of my to do list. If there is something that I can do externally to get the economy into the acceptable range it would be the preferable solution. Thanks for the offer.