Re: Help! My Focus Has Gone Crazy!!
Rough idle can be associated with a bad IAC sensor (idle air controller), located around the throttle body. Replacing the TPS is also advisable while you're in that area, as it's also a regular maintenance item. If you have over 100,000miles I wouldn't rule out a bad alternator. It'd be a good idea to get it tested if the problem still persists after replacing the sensors.
'11 Ram Quad Cab 4x4 SXT 5.7L HEMI (stock); 48,500m
'06 Pontiac G6 GT 3.5L 220hp; 64,000m
'12 Chrysler 200 Limited 3.6L 283hp; 28,000m
'99 Taurus 3.0L 2V Vulcan 145hp; 154,300m - Traded
Amsoil in all vehicles!