mpeel

Hello, I am new to the forum and would appreciate any help that can be given. I have a 1998 Malibu that has a continous CEL (code P0401) low EGR gas flow. I pulled the EGR valve and cleaned it thouroughly (wasn't really that bad), also blew out the channels with compressed air, and de-carbonized the engine with Sea-Foam while I was at it. After resetting the pcm the code stayed off for about a week, then returned. A new EGR valve is 180$ where I am at and I feel that is a bit much to change out while "shot-gun" trouble shooting, especially since I have heard of other sensors to blame, or a clogged intake (50$ for new intake manifold). What I would like to know is if there is a way to check the EGR valve or other related sensors, if so please explain. Don't want to pull the intake manifold off due to very little carbon build up at the EGR. Am more than willing to follow advice given, within reason and cost effectiveness of course, and report back my findings to hopefully help others. Thank you in advance for any help or suggestions.