My 91 is a California car with EGR. Yesterday, the CE light was constant, and KOEO test produced code 33. Turns out the EGR valve was stuck closed with carbon deposits. I cleaned it up with carb cleaner and Q-tips, got it opening and closing smoothly. Just trying to save $. Is it likely to be okay for a while or am I gonna have to go back in there with a new valve? Joseph van Oss