1992 Mercury Cougar XR7 V8 stalls when turning then battery dies

[MisterF0523]

1992 Mercury Cougar XR7 V8 sometimes (gradually worsening) won't turn over. when it starts it will run for a while and then stalls, or almost stalls (sometimes hitting the gas will keep it running) when I turn the wheel and then the battery is dead. It doesn't have to be turning to shut off but turning definitely makes it worse.Ive changed plugs and wires, fuel pump and filter, had alternator bench tested, not sure what else to do

 

[RLGL]

Instead of throwing parts etc at it. You need to figure out if the issue is fuel or electrical.

 

[herm0016]

any codes? it should be obd1 right?
sounds like the turning thing is just additional load on the engine via the power steering pump that kills it.
as rlgl says, electric or fuel, or maybe mass air sensor or vacuum leak? clean everything really well under the hood, and then look for cracked hoses or dirty connectors. clean the maf sensor. the battery may just die because it cant charge enough at idle or something, i think you have 2 issues going on.

 

[MtnMan]

Fuel, it ain't getting enough... There are literally dozens of reasons why that is happening, from the fuel tank to the carburetor.

 

[trenchfoot]

Start with the simple most easily detected problems and work your way into the more difficult ones.

On the electrical side, I noticed you mentioned doing a a test on the alternator but no mention of doing a load test on the battery. Have you done that already? Also, anything under 14 volts at the battery terminals while engine is running is a probable cause.