For about $14 and an hour of your time you can know for sure if your timing chain is the problem. Take your valve/rocker cover off and you'll have a good view of the tensioners to see if they're warn/cracked or not. If they're not, replace the valve cover gasket and put it back together and you're done. If they are, you can decide to continue taking things apart or put it back together and tackle it another day. Either way, you'll know for sure and it doesn't require any more effort than 8 bolts and any more cost than a new gasket.