Hey guys/gals,
Based on paleryx's description, I would say you pretty lost an entire rod/piston and a new engine is definitely suggested. Depending on what you plan on doing with the vehicle, I would look at either picking up a used engine from junk yard or on the Lotustalk.com forums (lotus guys sell their engines with less than 50k on them for about $1k -$2k in price). You can go with MWR or you can go with an engine from BOE Fabrications which builds race motors for lotuses and are in my opinion the best ultimate choice (their prices match as well though, sadly).
Hope that helps you out.
As for Superica77, yours is harder as it could be as simple as just a sensor is out. So until you can pull codes, it is hard to say what is wrong with it.