Alfa Romeo Repair: Over revving, lamba sensor, alfa 164

Question
Hi Stephen
I own an Alfa 156 2.0ts. When warm and idling the engine revs race from about 400 to 2000revs, the o2 sensor was replaced 18mnths ago and the lamba sensor was replaced 6 weeks ago. Also when accelerating away in 1st gear it feels like the car is towing something it doesn't feel as quick of the mark as my old Alfa 164 which was also a 2ltre but had less bhp. Please can you help!!  

Answer
The MAF sensor may need cleaning or the MAP sensor vacuum tube may be clogged. However, I need more info because what you told me is vague. For example, a lamda sensor and an O2 sensor are the same thing, also, do you mean the the rpm fluctuates at idle between 400 and 2000 rpm... If so you have an intake manifold air leak. Send more detail if possible.