So it only happens when engine is warm or partially warm?
Never ever when cold?
That wouldn't be ignition switch, it is a mechanical device and warm or cold engine wouldn't matter.
If the lights on the dash come on then ignition switch would be a long shot
If CEL(check engine light) comes on then computer has started up.
Each time you turn on the key you should hear the fuel pump Hummmm, for 2 seconds
Do you remember hearing that?
Check the Crank position sensor(CKP) on the main pulley, about 7:00 position, see if it is loose, long shot.
CKP times spark and fuel injection for the computer, computer doesn't even know you are trying to start the engine until it sees CKP Pulses timing when #1 is at Top Dead Center.
This sensor doesn't tend to be intermittent, it can fail out right, or be damaged, but intermittent is not a common failure
There really aren't alot of things that can prevent an engine from starting if starter motor is working.
No compression is a mechanical failure, so wouldn't allow a restart at anytime, so off the table
No spark is possible but it wouldn't usually "act like it was trying to start" at times.
I believe the Duratec 2.3l uses COP(coil on plug) spark so all 4 coils would have to fail for a no start or computer would have to fail, and I doubt it would restart ever, so long shot.
No or low fuel pressure can act as you describe, "tries to start" and a fuel pump is an electric motor that can be effected by heat, it does get warm, the gas in the tank cools it down.
Do you remember if the problem is more likely to occur when tank is at or lower than 1/4 full?
Because it is an intermittent problem there are no real tests you can do except at the time the problem occurs.
I would get a spray can of Ether(quick start) to carry in the truck.
When the problem happens, open the hood, open the air filter box and remove air filter, spray some ether into the intake
You can leave air filter out and box open.
Try to start the engine
If it fires up and then dies Spark is working but there is no Fuel
If it doesn't fire up then spark is the problem.
It is not good to spray anything into the MAF(mass air flow) sensor, but once or twice for testing is OK, just don't make a habit of it.
Another long shot but known to occur on the 2.3l is a bad TPS(throttle position sensor), but this is easy to test for when the problem occurs.
With a no start, open the hood and locate the TPS(good to find it before hand), unplug its wire connector.
Try to start
If it starts replace TPS, if it doesn't then try the Ether in the intake, you can plug the TPS back in.
All fuel injected engines have a "Clear Flooded Engine" routine, if you press gas pedal to the floor and hold it down before engine is started the computer will see 5volts from the TPS(foot to the floor) this tells computer to start Clear Flooded engine routine, computer turns OFF fuel injectors but leaves spark on, so an on purpose no start allowing you to "dry out" a flooded engine.
If TPS has an internal short then computer may get that 5volts and shut off fuel injectors.
This wouldn't tend to be intermittent, so a very long shot but not a no shot
Last edited by RonD; 4 Weeks Ago at 10:43 AM.