Hey man Ive experienced some of the same issues going on with your car. My OP goes lower than usual and it stays steady while I accelerate. The engine also misfires and runs like about 275hp. I know the engine needs a rebuild but im running it because its the only car I have that takes me to work. I decided the best decision I could make was buying a long block. I am buying a long block for $1500.00 and it has 48k miles but I have to say that I took me some time and patience to find this deal. You can probably find some good deals on craigslist but the best deals come through ls1tech. Salvage yards usually sell long blocks for about a $1k-$1400 with 70-80k miles but its a risk of course. Well I hope the best outcome for ya