1995 chevy k1500 when I press the brakes the truck stalls. changed the alternator and the battery and no change. Ran the poor boy diagnostic and it just keeps telling me the o2 sensor

no engine told and is a pure engine question + EFI
nor what was moved with the newer engine to the older car.
to the blind and deaf.
lost the scan tool>?
check all fuses.
battery fully charged

Hi, your basic symptoms will be. Your brake pedal. Will be very hard to push. When the pedal is engaged there will be a large vacuum leak, usually causing the engine to be very ruff or stall. If its bad enuff, youll hear the the air leak when pedal is depressed, hope that helps.

first you have to do fuel pressure test while engine running. The fuel pressure regulator is located on side of injector box
what about cap and rotor distributor have to be change
feel free to ask more info
hope it helps

Low power lean conditions cracked air intake tube GM Testing by a qualified repair person with proper diagnostic tools is the way to a proper fix , not someone guessing !

check to make sure the power brake booster is not leaking, do this by starting the van and just let it idle in park and push the brake pedal if the engine stalls or surges or you hear a sucking noise under the dash then replace the power brake booster if there is none of these systems then replace the idle control motor. GOOD LUCK

Check your valve adjustment ( rocker arms ).

You may have picked up some debris and/or water when it ran out of gas. That got sucked up into the filter. Try changing the fuel filter I believe it's located on the right side, just ahead of the rear wheel.
Try that and see if there's any improvment. Hope this helps.
Good luck.

Probably your master cylinder or could be Anti-lock. Are you loosing fluid anywhere?

Have you changed the fuel pump yet?I had the same exact problem.I replaced my fuel pump with an AUTOZONE PIECE OF JUNK fuel pump.That pump lasted almost 2 days.The second day i had it the truck didnt want to start but it did and it ran like ****,and when i put it in gear it ran as long as I didnt touch that gas pedal.You could go get a fuel pressure test or just replace it,your call.You might want to check your filter too but im sure its the pump.Good luck

try changing the mass air flow cencer