Opel Corsa Light+ 14.0 blue pipe plugs into

Hi All Eric is that your car? I have the same issue with my blue pipe. Awaiting for an answer. My car has been bipolar AF if you can say so, one day it drives perfect and idling is perfect. The next day when putting in my clutch the revs go low sometimes even dying, other days hops up and down the next day it goes as far as past 3thousand revs. The car sometimes jerk at a point as well. Sometimes it starts and idles perfect, some mornings i need to keep my foot on the excelerator to keep it running. I've recently did a minor service on my car, battery bought last year. Checked my alternator out, did loads of diagnostics, but only one sensor voltage was low - crank sensor. It was reset as well so now I'm so scared of wasting a lot of monies and then it can be something so simple so small. I've replaced the relay which is under the steering wheel, brand new mind you. Oh and someone tuned the nut behind the accelerator pedal thingy in the hood because my revs where sky high, and that seemed to help most of the days but as I said it revs how it wants to when it wants to Any advice guys???? I love my opel and I can feel her heart is in the right place still very strong but she's a bit under the weather and I don't like it :-(