My daughter recently bought a 2000 mercury villager with 175000 miles on it. It had the check engine light on, but was running fine at first. One day she got in it and it was bucking and jumping when she put it in gear and tried to take off. I hooked a computer to it and it had a knock sensor code on it, and cam position sensor code. On the code repair both had replace distributor as a common fix. I replaced the distributor and cleared the codes, now the car idles fine and doesn't buck and jump when you give it fuel, but it won't get over 3000 rpm in neutral and it starts bogging down, in gear it won't run over 2000 rpm without bogging down. I replaced the plugs, cap, rotor button and plug wires when I put the distributor in, and replaced the air filter and fuel filter at the same time, the air filter was completely plugged. I also had a vacumn hose bad on the egr valve and replaced it, with the engine warm I am getting 20hg's of vacumn and it's constant.