Hello everyone!!! I own a 1994 Cadillac Seville. Today, it shut off while my wife was driving it. It kept shutting off upon start up. After several attempts, it started. It was allowed to idle. While idling, it runs very rough. It seems the gas is not flowing through properly. There is also a hissing sound. There was some black smoke and the smell of oil burning. I was told that the fuel filter probably needs changing and there is possibly some trash in the lines. Also, there maybe either a loose hose or a hole in the line. Of course, I only use premium fuel. Does anyone have any ideas as to what is going on? Thanks, guys!

 

A hissing sound and black smoke sounds like a vacuum leak near the map sensor.
93 and 94 northstar engines have a sealed upper intake plenum with the map sensor inside.
If the seal fails or a large enough vacuum leak is present in the intake it fools the computer into thinking the engine is under load and excess fuel is injected causing the hard starting, rough idle and black smoke.

I use carb cleaner to spray around the engine while its running, this sometimes leads to the area where the leak is at.

Have you checked the computer for any trouble codes?

 

Thanks FLCaddytech, I will look into this tomorrow. Also, thank you for such a quick response!