Ford Mondeo tddi 2003 - driving home at 70 ish for an hour then revs kept dropping, after a mile or so down to 5 mph, then as I gave up and got onhard shoulder it picked up and went ok. Next day ok at 70 for 10 mins, hit traffic and revs dropped and recovered, then back to 70 and dropped again and finally died. Car would not start, fiddles with fuel pump relay and fuse, this took some 20 mins and then ok and got it 5 miles home. Sat with revs at
2,500 in garden and revs dropped on own to 1500 then recovered this repeats randomly sometime dropping to 500 rpm but throttle in same position. I did think I heard a quiet "clonk" a couple of times just before revs dropped.any ideas as hrd to troubleshoot unless tottaly dead. Petrol was from shell on M23 and used 3/4 of tank with no issues.