got a fiat brave 1.6 changed plug leads plugs coil pack the timing ok but it still miss fire use a lot of gas

Oh dear. Could be a holed piston, sticking valves, or just faulty spark plugs. Take a plug out and re insert it into the HT lead, earth the plug body on the engine and get some one to turn the engine over as if starting it, and see if the plug is sparking. Do this on all plugs one at a time, re-fit the one you have tested, then do the same with the next one etc. etc., and this might get you a bit further forward.

SIR ACCORDING TO MY EXPERIENCES MISFIRE DETECTED MY BE DUE TO THE FOLLOWING
1- HT LEAD NEED TO REPLACE.
2- AT LEAST ONE OF THE SPARK PLUGS IS CRACKED OR THE GAP BETWEEN ANODE AND ELECTRODE IS TOO SMALL OR STICKED
4- IGNITION MODULE FAULTS
5- ECU FAULT.
6- MAF SENSOR FAULT.
7- MISS CONTACT BETWEEN HT LEAD AND ITS SPARK PLUG.
( ALL OF THE ABOVE ARE ONLY FOR EF l )