Hi, I have a 2006 grand caravan sxt 100,000miles ...that is giving me codes P0306 and P0404 and it has a serious lack of power. I have changed the spark plugs, wires, coil, (Egr was new last year) .... next thing i was going to do was to switch two injectors and see if the problem moves. It also squeals when I start to drive ... and it's not the belts ... I tried to test for a vacuum leak with an unlit propane torch but found no change in engine rpm ...help... i could use some experienced advise
thanks in advance
Ps I also think I need to change the pcv valve as there is alot of oil residue coating the throttle body and it has been eating oil for a while with no drips or grey smoke

 

Have you tried doing a compression test. I would do a dry, running and wet compression test. You could have a burnt valve or flat camshaft lob.