Help P0404 Code

Well on the way home this afternoon the ole blazer seemed to not want to shift gears properly. After a few starts and stops the SES light comes on and seems to run fine in "safe mode" (with ses light on) Code says EGR range/perfomance whatever. Can anyone help me figure this out?

Thanks in advance,

Hunter

UPDATE. I took the ERG off and cleaned it no help there. I unpluged the electrical connector at the top and this seemed to help for a little bit but started doing the same thing (improper shifting, overheating, no power) the computer still only shows a P0404 code EVP Range/Performance. The truck sounds fine @ idle. Any ideas at all?

Update yet again!!! New EGR no help. What are the possibilities that the catalytic converter is bad? I guess there is no way to check this theory is there?