I bought a 1999 Villager for my husband's work van last year, and almost as soon as we got it, it went from smooth-sounds in the engine to a little roughness. I has progressed over the last few months to be chugging, won't start on first try, and runs extremely rough. Dealership told me last week to do a tuneup. I am on 60% disability and had my neighbor (who has done mechanic's work for years) and who has done other work for us, do the tuneup. NOW it runs rougher than before he did the tuneup. It is showing a check engine light and a code for a knock sensor; however the dealership said that knock sensor didn't affect the running situation of the engine and they would reset the computer and the code would then go away. I have a hard time believe it would be showing a code if something didn't need to be done. He threw a tank of higher grade gas in it today and has been wondering if it might be clogged injectors. The engine seems to have a "tick" in it. If it is anything more than basic, how scarey is this getting? Any thoughts would be deeply appreciated.