My 94 BMW 3.25I starts then putt and check engine lite comes on then the car cut off

you need to find someone with a obd11 code reader to extract the fault codes that will give you clue where to look for the fault. if its a v6 petrol they have problems with ignition coils and/or spark plugs, the spark plug resistance on the centre electrode goes high and can upset the onplug coil and give those symptoms'

not sure what you are describing really, is it possible you can elaborate? After you filled up this happened? The engine started cutting back? Did you put diesel instead of gas? A common mistake! This will make the vehicle putt putt if it even starts and will have no power what-so-ever! Will just sit there and putt putt. A plugged catalytic converter will get red hot and sometimes hiss if there is any leak you your exhaust and the car will overheat and have a loss of power and the hotter it gets the more the power loss will be until it overheats the head and warps it or blows a head-gasket.
If that is smoke from a fuel leak then this is dangerous of explosion.
If you had a service guy check your oil when you filled up, he left the oil filler cap off and it's spraying all over the exhaust and engine and again dangerous of fire. You must carefully determine what is leaking to cause this smoke, it's either an exhaust leak, an antifreeze (coolant) leak or from the power steering or transmission line or brake line. One thing to find a small leak is to place a piece of cardboard under the engine to see what and where anything is dripping.

I had the same happen to my 94 Corolla, it cut off while driving. Change out your distributor and adjust idle before tightening down.

have it checked for cam shaft sensor

2 possible reasons
1--- failed cat converter blocking the exhaust
2---EVAP system not venting the fuel tank properly
run the fault codes and have an exhaust shop check the at converter

You have a injection problem, whether it's a sensor or fuel feed . I wouln't drive the car untill you have issue addressed as you coul;d cause real expensive damage. The PCM will have to be scanned to find out the cause.

could be your fuel filter gummed up from the old gas

Is an oil pressure problem, inside the oil pan have an pump strainer , maybe its dirty
clean

pump suckin up garbage from the tank settlement from all the moisture or bad gas gel up the pump outlet line cause this problem.

Sounds like the fuel filter is clogged oe the fuel pump is on its last legs. Have you cheked the fuel pressure?