car stumbles then dies

1996 sohc, new timing belt, waterpump,mls head gasket and as the title say my neon will stumble then die after the motor warms up. it never dose it wile idling just after about a 15 min drive. i did the key dance an got a code 43. ive replaced the plugs with stock champs, put on new plug wires and replaced the coolant temp swich located in the back of the head. car still does the same thing only with no codes now. any one have any ideas...........

car has either skipped a tooth on the timing belt. or the pcm was never reset if so unplug the battery for two minutes or so

car never skpped a tooth it was just time for a new belt and i unpluged the bat and cleaned the cables while i did the plugs wires and temp sensor. btw the car had this same prob. before i did the head gasket and timingbelt. im thinking mabiee a cranke sensor loosing ref signle after it gets hot ......... i dont know this is my first neon. the car starts and runs fine when cold...it has never done this while at idle in the drive even after about a hour, but drive it more than 15 min and it bucks real hard the rpms jump real bad then it dies...let it sit 20 min and it starts right up and drives fine for about 10-15 min the its the same thing again.

Check the coil pack for any cracks.

map sensor I would check then it may not be working.

good chance the stumbling poroblem is connected to that

I had a similar issue with my '98 and it was the Crankshaft Position Sensor (CPS). She would run fine until the engine warmed up and then sputter and die. If I let her set and cool down off she went (for a while). The crazy thing was she would not code out with a cold engine, I only caught her by letting her idle until she died and then putting a scanner on her. I replaced the CPS and all is well.

i replaced the crank position sensor today and it seems to have fixed the problem.