2005 zx3 2.0 Duratec stutter/shudder

[whynotthinkwhynot]

Before you go tearing into the internals of the engine, why not pull the serpentine belt and check the rotation of the pulleys. You can also consider the alternator. Those tend to go out around 100k -120k.

You can also check the PCV line. Some FF's have reported it to be split causing idle and running problems. It is not easy to reach. It is located between the intake manifold and the engine block. The PCV valve itself is up above where the oil filter is in a black box. Follow the short, 6" tube from that black box to the intake manifold. That's the PCV line. You should be able to grab it and tell if it is split.

Tumble flaps are the cause of the "valve noise" sound, and probably not much else. Mine have been bad since around 100k, and I now have 150k.

You should really consider the KISS theory before you end up either taking apart a perfectly good engine and screwing it up, or spending a lot of money on something you don't need.