I replaced my fuel distributer with a used one, the 2 cylinders that were not working before are now working. I did not know how to adjust the EHA valve (black box on side), just used the one that came with fuel distributor. However, My car is running very rich, can you adjust the EHA, how do you do it, where do I start to diganose, I disconnected the cold start injector it made no difference. If i pull off one of the vacumn hoses it runs faster but not as rich, with the extra air. Can you identify the usual list of suspects to investigate. It starts right up, idles nicely (800rpm) has plenty of power, just running VERY RICH, with clouds of black exhaust.