Hello, I have been having an aggravatingly intermittent problem on my probe. It is a 2.5L V6 with a Manual Transmission and has 160K Km. I recently had both valve cover gaskets and intake manifold replaced to fix an oil leak, that also lead to new spark plugs, wires and fuel filter as well as a tuneup, but the problem persisted through this. When idling at normal temperature the revs will occasionally dip and the engine will " chug" a little causing the car to shake and this is accompanied by small " pops" which can be heard coming out of the tailpipe. Then under normal acceleration the car will hesitate/stutter, this happens in any gear usually around 2000rpms. What do you think the problem could be? Please help.