90 cougar 3 questions

I own a 90 cougar ls with 150 000km on it. It is a daily driver but it seems to hesitate off the line, its really bad when its cold but it does get better as it warms up. I thought it was an o2 sensor but just checking here first. my next question is I seem to have a rattle in the back of my car but it doesn't always have it, just now and then and not for very long periods. my final question is when I idle in traffic the car idles rough but when I shift into neutral it runs smooth is that related to the first problem or is it something new? any help would be appreciated

this is not the turo is it? first thing i'd do is make sure all vaccume hoses are good and not leaking,and have you done tune-up latly? gas filter,plugs,wires,air filter? may want to check fuel pressure ,coil pack and you can unplug 0-2 and start it and see if it makes car run better or worse?