u/Icy-Control9525

I was getting codes for misfires. Checked my plugs, the passenger side all had oil in them. Changed the plugs. Few days later. Same issue. Noticed the valve cover gasket was leaking. Grabbed a new gasket. Went to change it, noticed all the bolts were loose. Tried to get the cover off. Couldnt. So i thought maybe tighten them up, grab a more knowledgeable friend before i beeak anything. Replaced all the hoses and wires i disconnected. Go to start the truck, she runs. But, she wont move unless i revv high. Shifts into gear fine, no rev at idle. Idk what ive done wrong.