How many miles on the engine? I forget the schedule for the crankcase filter, but pretty sure its around every 50,000. Did the shop explain what wrong wrong w/ the egr valve or just trying tio sell parts. I do these on the ISM engines all the time, our cost is about $800. W/ a bad valve you have a definate power problem, dont think it would mess w/ the fuel economy that bad. And ya, being in cali, dont listen to anyone about deleting all the emissions stuff, it has to stay. What Ive seen people do to get around it is do all their deletes and the tune that come with it, and just keep all the parts on hand in case they need to put it back to stock. Cant recommend it though, sounds like a giant pita.