Love this - Lets Talk fiat
In Bold letters
(DONT USE THIS SECTION TO POST MODEL SPECIFIC QUESTIONS)
lol
Anyway - Dont eliminate the ECU just yet - every1 blames the poor ecu
Since plugs and HT leads are new - Ensure each plug is sparking
and Find out which cylinder ISN'T firing
If all cylinders are firing - Could be the timing belt has slipped?
The HG is blowing/leaking between channels - I'd get wet and dry compression tested - Ask for the results written down - so you can post them here
failing that it could be an injector issue - not fueling? or over fueling
Since you've lost power - Juddering could be engine rocking due to overfueling - EML on, COULD forwell mean the Temperature sensor has gone either way
Find out what the EML is on for
Get a compression test
If you want - Spend £15 get a suitable Diag lead - Use a Netbook/laptop and do the diag yourself with the Fiat Ecu Scan
Its free and works on engine management
ziggy