Hey guys had a big problem with my car lately. It seems to swing left and right somtime when im driving down the road which i have to make constant corrections for even worse, Near me there is a motor way slip way that is a huge left hand turn much like a nascar track that decends on to the motorway...they car seems to have a problem when turning left especially as it catapults the car left then right as described previously. What could this be as it dangerous and im starting to worry!!
Cheers guys, any help much appreciated

also

Prob guys, my engiene light keeps coming on now and again and i have to connect the battery to reset it. The car seems sluggish when its on and seems to make a slight gargling noise when accelerating and at a standstikll. ive got a k&n typhoon fitted dont know if it could stem from this?

The car is an st170 focus or svt in the states.
Thanks very much for any help you can give guys