There was a recall on the 1978 model; Honda overhauled a lot of these CVCC engines. By the end of the 1978 model run, the cylinder head and exhaust system had been completely redesigned and the problem was solved. The 1978 model also had a notorious habit of trapping ice/salt sludge in the front? fender wells, causing very rapid rusting; Honda replaced a bunch of fenders on that model. I was so fed up with that car that I traded it before the recall notice came out. The 1978 Honda Accord was a major POS. CVCC = controlled vortex combustion chamber. As I said, by 1979 the problem had been solved. The 1978 model has often been listed as one of worst cars ever built.