[PWGuy]

Originally Posted by Top-Ace

I am having the EXACT same problem with my Zetec ZTS. I have replaced plugs, wires, coil pack, fuel filter, air filter, pcv valve and hose, oxygen sensor, DPFE sensor, EGR solenoid, probably more I cant remember. I have a Snap-On Solus scanner and do not see any problems. Fuel trim is at a rock solid plus or minus 2, so no vacuum leak.

It is also stumbling when very cold at start up. Also less power going up hills.

I am getting around 24-25 maximum MPG all long distance highway, much worse in city. Honsetly at this point, I think the timing is slightly off. Maybe the exaust side cam timing is off a few degrees, which i know can cause these symptoms.

So changing the timing belt will fix this or is more required to fix, if it's an exhaust side cam timing issue?