Quoting: philoldsmobile
sounds quite a lot like the distributor was damp, a common problem with all cars of that ear. Mine was like that when I bought it, (got it cheap because it wasnt running right) but a new cap, rotor, leads and arm transformed it. I used to get nearly 40 mpg on the run to stratford upon avon
I tried all that, serviced it several times, it was just a rubbish engine - the one in my Volvo anyway.
