Have you inspected your MAF lately?

Modern Fuel Injection engines require the measurement of the air into the engine.
The common Mass Air Flow sensors available include:

• Hot Wire
• Vane Type
• Hot Film
• Karmen Vortex 
• Speed Density

 The MAF found on the Lotus is of the Hot Wire type.

   Most common hot-wire MAF sensors use a platinum wire or filament heated to a prescribed, maintained temperature above ambient, located centrally in the incoming air stream. These sensors function on the electrical principle that resistance decreases with temperature. As intake air moves past the wire or film, the cooling effect causes a measurable drop in resistance, and thus lower voltage is required to maintain the prescribed temperature. The hot-wire MAF control unit is sent a reference voltage of 5V, and returns about .4V to.5V at idle and from 4.5V to 5V at full throttle. Based on a fixed data set, an accurate assumption of air mass is made. 

  However, when these sensors become contaminated, they can send false readings to the Engine Management system and cause driveability issues. 

Cleaning these sensors is quite easy and can restore performance to your engine. You will need Mass Airflow Sensor cleaner. Do not use anything other than this, as other cleaners (ie. Brake or Carb Cleaner) can leave residue on you sensor

After cleaning, you should not see any dirt and that the wires are clean.