Multiple issues

All I seem to be getting lately is issues with this car! When I start the car up, it idles at just over 1000rmp then as it sits idling it drops slowly to below 1000rpm. Is this normal?

While it's sat idling below 1k, the car feels like it vibrates every couple of seconds. I'm also getting some performance issues. When I accelerate quickly the car seems to lag and then gets like a power boost - it's almost like what happens in a car wiht a turbo, except mine hasn't got one. I can hear what sounds like air escaping beneath me when I have the window down.

Car only had a service few months ago.

I cant keep going to the garage...I knew this car would cost more to repair etc but wont have any money left at this rate. Steering rack got some play in it as well which I know isn't going to be cheap! Should I just sell this car before I am unable to (financially) repair it?
 
All, if not most modern cars will always idle high on startup. It’s to get temperature in the cat.
Your power issue, I’m not sure. Does it have any fault codes? Does it sound louder than usual like the exhaust is leaking?

If you’re worrying about replacing the steering rack as a financial burden, yes you’re probably best off selling to be honest.
 
All, if not most modern cars will always idle high on startup. It’s to get temperature in the cat.
Your power issue, I’m not sure. Does it have any fault codes? Does it sound louder than usual like the exhaust is leaking?

If you’re worrying about replacing the steering rack as a financial burden, yes you’re probably best off selling to be honest.

I haven't got a diagnostic tester so can't see if there's any codes. There's no lights coming on in the dashboard. Doesn't sound louder than it should, just sounds like there's a small hole maybe...almost sounds faintly like when you let the air out of a balloon really quick, just quieter.

Also discovered I have a coolant leak as well! Topped it up to the max (while cool) the other day and its empty today. I just can't do anything right with cars, honestly.