3800series2

I had a decent coolant leak, and the mechanic said the plastic elbows were urgent, but the upper intake manifold gasket and valve cover gaskets also had leaks. I can't remember if he mentioned about the lower intake manifold gasket or not. I had him do the aluminum elbows and I wanted to do some...

Ok so I have a P0420, P0442, and a P0303 code on my 2003 Buick LeSabre (3800 series 2 engine) And I think they are all related to one another...I've done lots of research and somebody said that one of the possible causes of the misfire on cylinder 3 (P0303 code) could be caused by a evap system...