Hi folks, thanks for all the info I've read here to date. I have a new issue with my 98 that I need some info on. My engine that was pretty quiet for the 260 k miles on it has developed some strange noises. Without too much detail I have to say it sounds like perhaps a timing issue.. too much advance. Came on all of a sudden and noticed at startup. Today when I got on the freeway and exceeded 60 or so (about 2350 RPM's ) the check engine light started flashing. Previously the light would come on for a week or so then go off for weeks and reappear. Seemed like it liked to flash 4 times mostly but at times flashed more. It stopped flashing when I got off the freeway and kept it under 60. (but stayed on) I did have a replacement head installed about 4k miles ago. Knock sensor? (don't even know where it is) Some kinda sensor???? Thanks for any input.