Terrible milage and dtc help!

[Kyle_KleinSS]

Ok guys my truck is getting terrible milage. I am at 3/8 of a tank and only at 270 miles. I have the 38 gallon tank. I am stumped on what is causing this. I recently put in the "new and improved" cps, the dark grey one, PN 1876736c91. I just read today that is for 94-96 trucks? I had my buddy scan it and found there codes. P0340 bank 1 cps error. P0475 exhaust valve malfunction, im guessing thats cause my ebpv is on a switch. P1249 wastegate error. Would these affect my milage? The truck runs smooth as butter no loss of power or anything. Air filter is new, oil changed back in december about 2k miles ago. Fuel filter isnt the best as my bro put 10 gallons of waste motor oil in the fuel. It gelled up that day but I left the drain valve open and pumped the oil out of the tank. This was probably 3 tank fulls ago so Im assuming its all gone by now. Fuel filter is getting changed at next fill up. Also I was thinking of putting my grey cps back in? I am at a loss, I cant afford to drive the truck getting this kind of milage.

Sorry for the long post guys, any help you can offer is greatly appreciated. I just want my baby running normal again! Thanks again this is a great site learned alot so far and looking forward to more!