The car starts up with rpm at around 2 or 3000 then goes dips down to less than 1000 rpm and is very shaky. At some red lights, it shakes as though it will turn off. I'm thinking it could be O2 sensor, catalytic converter, something with the fuel system, or even drive belts. Any professional opinion would ve very helpful!

(power steering, power windows, power door locks, ac, accessories, radio, etc.) This came after I hooked up a portable booster (without car's own battery). When I turned on the key the horn came on but when I turned the key off and started the car, it started.

the starter motor has been replaced but it is still doing it and it makes me think that the starter shouldn't have been replaced and its something else

The check engine light is on and the vsc light is flashing and it's off

When I put it into drive it made a clunking noise. It felt like I wasn't giving it any gas, so I pressed harder on the accelerator, and it still barely moves. The CEL is on. I checked the gas cap, and it was tight, and there are no visible cracks in it. I called the dealership, and they suggested having it towed so they could check the code. They suggested a computer problem or transmission problem. Any ideas?

While driving today, I started to hear an intermittent clicking sound. Then while walking towards the car, I saw what looked like a long connecting part under the front section. It was split with each part dangling down a little bit, but not touching the ground. What is it? And is it safe for me to drive.

Nobody was around the car when it did it i had to unhook the battery cable to get them to go off

Started last week, the first day, all my dash lights went out, power steering stopped working, and then car wouldn't start at all. (Had been making a weird noise about a week prior). Towed to shop, they said the alternator needed replaced. They did such (for $441). No more noise, problems starting, but idles below 1000 RPMS, when stopped, acting like its going to stall. Acts like its going to shut off when your slowing/stopped and turning the steering wheel, whether at a stop light, backing up, or sitting in park. Please help!!!

My car sometimes will hesitate to down shift for going up a steep hill for example. When it does downshift it's a very hard and jerking downshift to 3rd. It's an 4spd automatic tranny and the fluid is brown. Not sure if something serious is wrong please help!! The car only has 80000 miles on it. Should I trade it in?