I have a 2000 Windstar with over 76000 miles. I recently had the fuel pump replaced ($585). The same place that did the fuel pump told my wife that the van was in need of a tune-up for another $256. I told my wife that I could get the plugs and wires for about $50 and do it myself. So, I replaced the plugs and wires, also cleaned and oiled the K& N air filter. That weekend we went out of town to Phoenix, AZ. Halfway there the check engine light comes on. When we got to Phoenix, I took the van to an AutoZone and had them check the codes. One of the codes was cylinder 5 misfired. I told the guy I just replaced the plugs and wires and the only suggestion he had was that it could be the ignition coil pack, he than cleared the codes. I did notice however that sometimes when starting the van, white smoke would come out of the exhaust. This only happens on occasions. Since we’ve gotten back home the check engine light has come back on and once again I took it to AutoZone to get the codes read. This time the codes pointed to a bad O2 sensor. Could the oil on the K& N air filter cause the O2 sensor to malfunction? What would cause the white smoke? I also have some issues with the brakes. About six months ago I replaced the front rotors and pads and the rear drums and shoes. Now when you go about 5 MPH and you brake a loud squeaking sound (like metal on metal) comes from the right rear wheel. It only seems to happen when you’re driving slow and then braking, like in a parking lot. I’ve pulled the wheel and drum and I didn’t see any obvious problems. I even went as far as checking the other drum and the front two brakes, still nothing. Any ideas on this problem? Any help would be great. Thanks.