94-GMC 350 Made gas mileage Less By changes?

I vote CAI and coolant not hot enough. 195 is a good balance of fuel economy and a decent buffer before overheating.

Newer vehicles run 210-240 to heat the air as hotter air is less dense, requiring less fuel to maintain target AFR.

Most CAIs hurt horsepower and fuel economy. The OEMs spent way more money designing that air box than just about any of the aftermarket companies could afford. Most dyno comparisons prove this unless your parts are from a real high dollar firm...