I'm starting to think its the precat/rear manifold as well...
I don't mind doing the work myself, but seeing how rusted the nuts are, I don't think I can get it off myself. Plus the extra effort of removing the alternator....My local scrap yard has used ones for $125cdn.
Seeing you're from Pickering, do you know of any place that would either install a precat (or gut my exisiting one) for a decent price?
