2000 Dodge Neon what can be the problem

Start by checking the diagnostic fault codes. Chrysler makes doing that yourself real easy. Cycle the ignition switch from "off" to "run" three times within five seconds without cranking the engine, leave it in "run", then watch the code numbers appear in the odometer display.

The two main suspects are the crankshaft position sensor and the camshaft position sensor. It is common for them to fail by becoming heat-sensitive, then they'll work again once they cool down for an hour. Typically they cause stalling after the engine warms up, but they are also affected by "hot soak". That's when the heat from the engine that was blowing away during driving migrates up to the sensors when the hot engine has been stopped.

Absolutely not. The thermostat is in the cooling system. When it sticks open, coolant flows too freely to the radiator and the engine won't reach the proper operating temperature. The heater will blow cold air. When it sticks closed, or it stays closed due to a leaking cylinder head gasket, the engine will overheat.

Not exactly. The diagnostic fault codes are set when the Engine Computer detects a problem, and it turns on the Check Engine light if that problem could adversely affect emissions. Very often a code won't set for these sensors, but if one does set, you'll know which circuit needs to be diagnosed. Reading the fault codes doesn't fix anything. It just tells you where to start looking.

Normally you need to plug in a scanner or simple fault code reader to read the codes. Many auto parts stores will do that for you for free, but you have to remember, they aren't mechanics. All they know is selling parts. Fault codes never say to replace parts or that they're bad. They only indicate the circuit or system that needs further diagnosis, or the unacceptable operating condition. When a sensor is referenced in a fault code, it is actually the cause of that code only about half of the time. You also have to look for wiring problems.

Chrysler is the exception to this. They have always made it real easy to read the fault codes yourself. You don't need a scanner or code reader, but all you'll get are three-digit numbers, so you'll need to look up their descriptions. Post those numbers here, or you can go to this page:

http://www.2carpros.com/trouble_codes/obd2/P0100

I haven't bought any sensors in a long time, but as a guess, I'd expect them to be around $50.00 to $70.00.

You can go to the parts stores' web sites to find out for sure.

1) Throw a dart at the board.
2) Visit a psychic.
3) Spin the bottle.
4) Throw dice.
5) Cut a deck of cards.
6) Draw straws.
7) Read the fault code(s).
8) Connect a scanner to view live data and see which signal is missing during cranking when the engine doesn't start.

To be serious for a minute, you need the right tools to build a house, prepare lunch, and wash the dog. Different people will use different tools to accomplish the same things. A scanner and your mechanic are tools used to determine the cause of the problem. Chrysler gives you one more than other manufacturers. That is the ability to read the fault codes yourself.

We don't have that code number on our list so I'll have to dig up a service manual when I get home. I've never run into that description before. Nothing related to the oil pump is monitored by the Engine Computer, so I don't know where that code came from.