My SC'ed 1995 threw a PO401 code about 6 months ago. Cleared it with the scan gauge and forgot about it. It threw the code again and I am getting ready for a 7 hour trip this weekend. when I researched the "cure" I found several threads outlining the process to diagnose the various components on the EGR system and dial in on the faulty component. I work so slowly, I just do not have the time to do this properly. If I were to just slap in a part and cross my fingers, is there any consensus as to where the fault lies, say 90% of the time, with a PO401 code?