96 850 GLT bogging down.
 

Need help badly. Filled tank. Shortly Engine lite came on and engine bogged down and died. Replaced fuel filter. Checked fuel rail pressure Ok at 38+- lbs in idle and increases as it boggs down.OBD2 scan shows Mass Air Fuel Sensor. Engine will start & and idle fine for several minutes and then start bogging down. I can keep running for short period by pumping accelerator and engine up to 3000Rpm+- but will then just bog down quickly and quit. Wait a very short while. Engine will start againg and run Idle Ok then shortly will do the same bogging down. Moments after it quits ,I can restart and idle OK then down again. Help please. Would bad MAF sensor cause this or bad map sensor.

I have the same issue on my '96 850 (non-turbo) I also have a hesitation while accelerating. I've replaced the fuel filter, cap and rotor, throttle position sensor, map sensor, air filter and cleaned the throttle body. none of this fixed the problem. If you find a solution please post it up!

This may be simpler than you think. You state that the problem started just after you filled your tank. It may be the gas you put into the car. Was the car behaving normally before you changed the gas ? I made a similar mistake when I first added gas to my 850 GLT. I had always run on 87 octane (which is the equivalent to 85 Octane in other states) in my other cars. So, without thinking I filled it up with 87. The next day my car ran like crap. I siphoned off as much as I could, then filled it up with 93 Octane. The car ran fine. On the other side of the spectrum, a few months ago I added fuel injector cleaner to my car. The tank already had 93 octane in it. Again I had problems but not quite as dramatic as the first instance. My mechanic told me my problem was probably caused by the fuel injector cleaner. It made the mixture too rich. I ran the tank out and filled it with 93 octane. The car ran fine. A third option is that you may have just bought a batch of bad gas.
My diagnostic scanner indicated 'fuel mixture' in both instances. I did not have to start changing parts. I just changed the fuel.