i also bought a new battery. what is the problem? why wont it start?

I have received advice from about a dozen people. Each has a different solution. Basically, I am told to complete a "drive cycle" that is highly involved and looks like it will be very difficult to perform.

If am going to do that and if that doesn't do it, my mechanic said he will do it for me for $150 and not return the car to me until it is ready to pass. I suspect I am going to be handing the car over to my mechanic in a day or so.

But I want to know, how did this happen? How did my car's computer (the OBD) suddenly become "not ready" with regard to the catalytic monitor? Because I don't want this to happen again. If it was something I did wrong that I can prevent doing in the future, I want to know about it.

Past month noticed the car would start to vibrate so bad while driving I had to pull off the road. Get back on the road and can't duplicate. This has happened three times in last two weeks. One time I just slowed down until vibration went away then sped back up and all was good.

After driving for 1 hour car will no start. Leave it to sit overnight and the car starts.I changed the CPS and still the same situation

The complete dash goes blank and sometimes it start and shut off immediately.
The humming or idoleing sounds are only heard during the blank dash. What could cause this it has approx 74,000 miles?

Battery was down and jump started, car runs fine with no problem but red light on dash board comes on and states that take to shop.

I can drive it for a day and park it for the night. It would be dead the next day. I just put a new battery in, so that is not the problem

service c on the screen in my car . just want to know what is that mean or what should i do?

you let of clutch too soon, I have it in the C comfort