Car won't run.Turns over & sputters, but won't stay running.

just about everyone does with either an old car or a new car with high mileage.how excessive? is oil consumption.well first thing is to check for oil leaks either underneath the motor or any oil lines feed into the motor .any major leaks would be pretty noticeable.if none are present then one would assume that your motor is burning the oil through the exhaust system .check to see what color smoke is coming threw the tail pipe.blue or black smoke indicates oil burning white will indicate engine coolant burning.in any case some color smoke is normal just depends on how much.so lets say your exhaust smoke is normal still could be burning oil just not a noticeable amount.on average you shouldnt have to add anymore than 2 quarts a month or every 1000 miles .depending on your driving conditions if you are having to add more than this there would be a leak some where or heavy color smoke.keep up on oil changes and always add lucas oil usually 1 quart its alot thicker than conventional oil so it reduces engine wear and will handle any small leaks in the engine components like the pistons and rings.if problem still present get to a dealer or certified mechanic as soon as possible good luck.

check the plugs again and see if they are oily again, if they are NOT oily check the ignition coil if it is giving current to all four plugs, if not ,change it.it might be shorting out when it is hot.........If the plugs are oily again, and assuming the valve cover has been changed,sorry to say you have an internal eng.piston ring problem. more tests must be done to pin point the problem.

sounds like you got some water in your gas ,, or your mass air flow sensor is shorting out , or dirty

Mass air flow , crank sensor . I wouldn't discount anything . Having a scan tool that can view engine sensor data would be a great help too , testing fuel pressure and flow and back pressure test the exhaust .
058 Engine Hard to Start or No Start Lean Fuel Condition
055 Engine Hard to Start or No Start Scan Data for EGR
057 Engine Hard to Start or No Start Ignition Module Test
007 Catalytic Converter Testing

is the coolant level staying full or do you have to add ? the moisture in oil cap is normal for an engine that sets, condensation forms as the engine cools down.the smoke you noticed may have been moisture burning off the exhaust as the engine warms to normal operating temp. you need to drive the truck to see if it starts to overheat or run poorly. letting it set or just starting it up for a while will most likely not help find a problem.

sounds like a fuel pump failure,check the fuel line pressure with a gauge ,on the fuel delivery pipe where the injectors are their is a valve like a tyre valve ,you should read 55lbs here for it to work properly.

check the exhaust manifold.It is prone to cracking at the expansion joints.Causing you to smell exhaust and confusing the upstream o2 sensor

tuneup either u have a bad plug wire or a bad plug sometimes the coil pac could be breaking down but im leaning toward tuneup.

If your test drive was short, but your drive home is longer, it could be a coolant leak. Coolant creates a thick white smoke when it burns. If it's coming out of the tailpipe, then it must be coming through the engine at some point, possibly from a failing head gasket.

A fairly inexpensive test for this is to drain and flush the radiator, refilling it with water, running the engine to warm it up, then drain and flush again, refilling it with water. Be sure to drain and flush the overflow reservoir as well if you can. And please be careful working with a hot radiator - steam burns skin very easily. This should remove at least 75% of the ethyl glycol antifreeze that causes the smoke.

Now, when you run the car up to temperature, if it still smokes white, but much, much less, then it is in fact coolant leaking into the engine and being vaporized and pushed out through the exhaust. The most likely point of failure is the head gasket - which means a several hundred dollar fix.

I think you have made a correct diagnosis. The loss of power and water from exhaust all point that way.