looks like toro rosso is getting the renault testing thing on their plate. 20 seconds off pace sounds like trying to get any form of intel on this failure of an engine, and by the sounds of it, this is not an easy fix.
i remember having one of my previous cars where i placed a 'performance' chip which turned out to have a flaw. the engine had exactly the same sound, misfiring and essentially damaged the pistons and valves of the car. if it really is 'just' the computer/software, it should be easily fixable. but since that hasn't happened yet, i'm thinking it's either a flaw in the engine itself, or a flaw where the renault engine is unable to correctly work together with the hybrid material.
magnetic resonanse has been mentioned, which essentially could wreck havoc on the computer, resulting in the engine behaving like mad. but in the end that still means there is a huge design flaw.