This car has a very difficult to trace intermittent problem of cutting out occasionally---usually on a downhill. Not electrical since there are no observed dash lights function drop offs (rev-counter etc)----and all symptoms point to fuel prpblems. Engine has been checked for fuel pump electrical integrity amongst other things--the pump and it's controller electrics were replaced two years back.
Now the car will not run. It occasionally starts and runs for a few minutes---then cuts out. after much trying to restart it then eventually fires and the engine goes backwards for a turn or two combined with a large puff of smoke from the lower radiator area (I fear from the sump or front crank engine oil seal area). This is my homespun prognosis believing that the fuel flooded engine occasionally pre-ignites giving this phenomenon).
We can have this car towed to a Merc garage but the distance is great and the car may only need a timing module or some small thing changed.
It is very well maintained and apart from this failure runs exceptionally well--like a new car. When looked at by the Merc' people during earlier intermittent stoppages (occuring say once a month) they could find nothing wrong.
Is there something I could do or have checked on specifically and can that puff of smoke be explained? I fear too that some things like cganging fuel filters may not have been done as regularly as claimed. Would it be a god idea to change this if I have any doubts?
Car has done 100 000 miles.
Guidance will be very much appreciated