Hi all,
my 8 valve punto with 151000 miles has progessively devloped really rough
running,ie mis fire.
I have changed all the electical items,no joy.
All 4 plugs are dry and black and sooty.Would this indicate the valves are worn,
Whats the best thing to do.
If the rings were worn the plugs would be wet.
So should i look at gettingthe head done.
any help appreciated.
tony

Obviously (?) a compression test (dry and wet - tells if it's pistons or valves) is a next logical step.
Valve stem seals are also the source of oily residue on sparkplugs and valves (which helps to burn them).
Sooty dry residue may be caused by rich mixture (air intake, fuel system, exhaust, timing - can be bad).
At such mileage (151 kilo miles = 242 k km) all problems mentioned above are possible (all at once).

But don't worry. The 8V FIRE's are simple and easy and cheap to fix (DIY or in the pro engine shop).