Alrite guys, I've got a 93 blazer with the CPI Vortec. I've been getting a consistent 8-9 miles per gallon, 11 mpg city and highway. Anyways, first I pulled the intake and the regulator side was a little washed but nothing horrible, but while I had it off I replaced the regulator. Still bad gas mileage. I hooked up our gm scanner at work and did the tests for everything, checked history codes, ect. EGR was operating fine, IAC system was operating fine. MAP sensor voltage low. Replaced and cleared the code, and re scanned a couple days later and that problems fixed. Oxygen sensors are operating fine. Exhaust does not smell rich or anythign(I have no cat). It runs like a raped ape, idles a little rough once in a while right at startup. I ran fuel injector cleaner and seafoamed it. My intake manifold tuning assembley is also new(broke the old one taking it out). My vaccum level is good, fuel filter has been changed less then 5000 miles ago. I always fill up every friday so the fuel level doesn't get down any farther then 1/2 a tank. I can not figure out while my gas mileage is so poor. Any other ideas? My intake air sensor and coolant temp sensor always are operating fine. I popped the Intake manifold tuning assembley again today to check for wash and there is none.