I have just gotten a beautiful 79 DeVille. It had been sitting for some
time and I am going over the problems. The car ran strong but needed a
radiator, master cylinder, new brake lines and a few other small thing.
While I was testing the radiator repair, I had it running for about 20
minutes. The idle slowly decreased until it almost stalled and the now it
barely runs and blows black carbon out of the exhaust and you can smell the
raw fuel. I replaced the ignition module as I had another car do the same
thing but that was not it.