My mustang was running fine then when I started it started stalling now it lost all its power it shifts late it runs real rough

SOURCE: Running rough and stalls during wet weather otherwise runs fine.

Your ignition coil is cracked. Replace it with a new OEM unit.

SOURCE: 98 ford escortLX starts and runs for about 1 min and then stalls

check fuel pressure regulator.+ vacuum lines going to it look see if gas in vacuum line.if so regulator rupture.

SOURCE: running rough/service engine soon light

WITH A #8 MISFIRE U NEED TO REMOVE THE PLUG AND TAKE A LOOK.THE SMOKE FROM THE EXHAUST SOUNDS LIKE RAW FUEL.BAD PLUG,COIL OR INJECTOR.LOW COMPRESSION?

SOURCE: 1965 Mustang 289 2v 2100 carb. The car runs fine

It sounds like the choke may not be opening completely. Check the choke tube from the choke assy. to the exaust manifold. The tube often breaks off at the manifold. There was a repair kit from a co.
called toke.(it was the 60's)The part# was ux-1 it had a new copper tube+sleeve and a fitting, that you would place over the broken piece in the manifold tap
it with a hammer and it knocks out the old + installs
the new fitting. Push in the new tube and install the
other end into choke assy. If it's an elec.choke check
the voltage at the wire to the choke assy. it should be between 7-12 volts, if not check for a fuse in line or at
the fuse block. I don't recall exactly where it is. But if
neccesery you can run a new wire with a 20amp in
line fuse, from the choke plug to the S(stator)connection on the alternator. This will provide enough
juice to expand the bimetal spring in the choke housing. And only when it's needed. When the engine is running..Also the choke can be adjusted
whether it's the tube or elec. You can adjust the choke spring by turning the black plastic cover.
There should be 2 arrows pointing clockwise+counter
clockwise. After the choke is fixed you can fine tune
it by loosining the 3 screws and turning to rich or lean as needed. Hope this helps.

SOURCE: Under heavy acceleration the car stumbles, runs rough

I am having the same problem with my mustang, have replaced tps, egr valve and sensor, clean maf, new plugs and wires, new fuel filter, cleaned throtle body and still having same problems....Please help!!!!!