i have a 2002 ford focus the zx5 version. my car doesn't have a check engine light on, but i have a rough idle when it warms up. rpms start fluctuating low and eventually it stalls. any suggestions? I replaced the pcv hose, pcv valve, throttle position sensor, cleaned the maf sensor, replaced the AIC valve, new battery, new coil pack, new spark plugs/wires, new fuel filter, cleaned the intake and throttle body. still no results. i have a pretty good obd 2, but i just dont know what to look for really without a code.