I don't know why the Chev. dealer can't fix my 98 Geo Metro?

I have sunk about 2 grand in my Metro now and ppl continuously keep on ripping me off. First the pulley bolt broke on the bottom and I have been having problems ever since. Every time I put my a/c on the car loses power and rides very slow just to get back up to 45mph and the service engine light has been on. I've taken it to several repair shops and they keep on saying it is computer code 400 and it is not the EGR. They said(Chev. Dealer%26#125; that my crankshaft gaskets needed to be replaced and that the part that the timing belt sits on was corroded so they replaced the gaskets and cleaned this part and they charged me 600.00 I am very up-set. It doesn't need an O2 sensor nor fuel pump so I don't know what else to do. Everywhere I'm taking it has cost me $600 and the minute I leave the car runs fine 30minutes later the service engine light comes back on. I don't know what to do.

I don't know why the Chev. dealer can't fix my 98 Geo Metro?virus removal

First.... engine code # P0400 Exhaust Gas Recirculation Flow Malfunction......

I would scan the computer again and double check the codes. This is either the EGR valve or the PCV valve..... I would change the pcv valve and change the EGR..... is your EGR brand new? If it isnt than change it.

I don't know why the Chev. dealer can't fix my 98 Geo Metro?anti virus protection