Please can anyone help with this issue. I purchased this 2009 outlook 6 weeks ago from a dealership. About a week or two ago the car started randomly bucking going down the road and threw a check engine light. It came back for a misfire on cylinder 4 and catalytic converter. Last week when driving home from work it suddenly started loosing power and bucking even worse sort of like when you get bad gas. It would barely make it up a hill, not pulling at all and the engine reved up high. Took it to the shop and had the coil packs, spark plugs, plenum and gaskets, catalytic converters and gaskets, exhaust gaskets and manifold gaskets replaced. Picked it up and within half a mile it is doing the same thing but there is no codes. Im lost on what could be wrong. Any ideas Note: I also had to put in 2 quarts of oil within a week with no leaks. Please help!!
Check fuel pressure and all 6 injectors. You can also have your mechanic pull all 6 spark plugs to inspect how they are firing. (to lean or rich, or fouled) while he's at it, have him take note to the compression of each cylinder as he pulls the plugs.