1992 ford f150 / 300 -6

Ranger not ford f100 Ranger.
When did it last run perfectly, last week, last decade or? never seen it run right..
lots of causes over up to 50.
I gets warm means engine,or outside air? temps.

so the spark plugs are bad or fouled. replace those old HV spark wires now.
it's over heating? the engine.
bad fuel
the classic answer is
bad engine, bad spark, bad fueling , in that order
or is the cause (or EFI failing)<< sensor etc.
this USA car (if is ) can OBD2 scanned easy, scan it.
do you want us to guess,? only.
or do tests, will you buy test tools to solve this?
there are tests for each cause of failure.
die out we call stalling engine,
when it wants to stall, can the fast right foot save the stall?
I guess car engine starts and runs cold? every time?
ever get a turn up,

engines 1996, diagnosis is best done, knowing first what is there,

2.3 L OHC I4, Pito LL23 4 cylinder but 8 spark plugs, yes.
3.0 L Vulcan V6
4.0 L Cologne V6

so when dead, and warm dead, check for dead spark?
check engine compression above 150psi on all cylinders
check fuel pressure when dead./

Does it run rough at hot idle ? How many miles ? Any recent work done on engine ?

What faults codes are showing on a test of the electronic engine control module?

I have the same vehicle, I found 2 issues wrong with mine. One was that a misfire in a cylinder, which meant replacing a coil. The other was that the IAC (Idle Air Control) was bad and needed to be replace.

check engine coolant temperature when it gets warmer, or at operating temperature, and verify that the temperature gauge is showing warmed up to operating temperature. If the coolant temperature sensor tells the computer the engine is cold it will over fuel and miss and the engine will die. When cooled down it will run fine until it warms up. Also could be coil if it starts missing after warmed up.

Your oil is a little low, and the timing may be off a bit but if it smooths out after warm it is probably ljust
low oil.

the p 0300 codes gives you the clue
it is random misfires and that is predominately from injector and low fuel pressure
pulling a plug lead will amke no difference if there is no fuel in that cylinder to ignite
bad coils will be a constant miss regardless
try putting a can of quality injector cleaner in the tank to see if that fixes the problem
have a fuel pressure tset done to check for pump, filter or pressure regulator problems

U have a leaking cylinder head gasket, both symptoms fit perfectly.

seem like you got the same problem as my scion xa, check the fuel pressure regulater. bad regulater some time smell like leak gas. auto zone might cause you about $80.00.

Sounds like you have partialy blocked heater core,not enough flow to the heater or heater tap either not working or only partialy open.You may have to remove heater hose at the fire wall and flush with garden hose.Also check if heater hoses are clear and running freely by using the same garden hose If you put hose up removed heater hose you should get a strong run of water coming out of the heater radiator.