First, we need to know what engine you have and anything else connected to its operation, for example, does it have a supercharger? My information says the 1994-95 Buick LeSabre has a 3.8L, V6, series L engine with PFI (port fuel injection). I assume this is what you have. The 8th character in the VIN code will be numeral "1" and the 10th character will be "R" for the 3.8 Liter, 1994 V6 Buck built engine. The spark plug gap is .060 inch and fuel pressure should be between 40 to 47 psi at the fuel log. If the fuel pressure is low, it may not start or run very poorly and behave as if fuel starved. One possibility is a clogged fuel filter. Water can collect in the filter and restrict flow. This problem worsens over time. At first, the engine starts and runs but bogs down as its load and speed increases, but will regain it composure when the accelerator pedal is let up. CAUTION: Relieve fuel pressure before opening any fuel line and loosen the gas cap. If the filter is lower than the fuel tank, be prepared to handle the possibility of fuel flowing out from the tank. This a very dangerous, fire hazard, task. You should have means for capping the fuel line upon removal of the filter, and this must be such not to introduce contaminants into the fuel line. If you are not trained to handle this, let an expert do it.

Another fuel delivery problem: The gas cap. The gas cap on a closed fuel system has a one way valve in it; it lets air into the tank and blocks out flow. If this valve gets plugged, it can cause the fuel tank to collapse or starve fuel to the engine. If the valve is open all the time (does not hold pressure), and the system has loose filler cap detection, the controller may let the engine run correctly at idle, but poorly at speed or at load. It allows a run-home mode, but not good load-speed mode. This can happen with an incorrect replacement cap.

You mentioned replacing the cam shaft sensor. This item can be troublesome, behaving when it is cool and misbehaving when as it gets hot. On some GM cars, this sensor is in the distributor taking on the function of "points" of older systems. On some GM models, an ignition module is in the distributor cap.

If you have a theft dis-abler (prevents starting by hot wiring), that can give problems.

Some computer controlled automobile systems looks for a tachometer signal and if it does not see one in a few seconds after starting, it will disable the fuel system.

Check out the ground strap. It should be in good shape and have good electrical connections at each end.

I do hope you have a good repair manual, else you will chasing ghosts. A good diagnostics shop can be very helpful.