Lately During these cold few months there has been a noise in the belt area (sounds like from a/c compressor area). I had tighten the belts due to squealing during moisture/wet mornings/days etc. Now might be to tight and causing havoc on a/c compressor? Anyways the other day I started car (very cold) and had a hard clunk kind of start up. I have been having issues with the camshaft sensor again from what experience showed me from the past in the summer/fall. All seemed corrected once I reset battery and tightened belts. Well After this kid of weird start up that morning...as I drove off and a red light come suddenly I stopped and A VERY hard downshift and kind of clunk noise in mid front of car. As I continue another 2 miles I go to pass a truck which TURNS RIGHT in front of me and I let off gas and WHAM another extreme hard downshift. So now I take it slower to go through gears etc at stops and go. I go pick up a trailer do a few runs with weight and such and return home...No problems since. Car has been sitting for a bit though and again now so I don't get stuck onto way to work etc. At least till winter goes away and warms up a bit. I have a heated garage (need to make room to get car in) but at least looking for an idea before hand (as I know cars pretty good) since this one time instance kind of confused me and looking for info if others had the same/similar issue? BTW no engine light came on or is on at this moment. Thanks for the help in this matter.