2002 mountaineer v6 car will start n try to idle then die scanner said bad oil sensor changed that n no change checked fuel pressure it fine checked volts to coil pack n it's fine ?? Frustrated

Pull the top cover of the timing, check the belt.

Had a 89 cavalier did that start then die it map sensor. Also check ground wires if the become too corroded they won't start sometimes just run weird

Is the check engine light on? you could have a bad ignition fail sensor, TPS sensor, or bad o2 sensor. it could also be a bad mass air flow sensor or a vacuum leak. without a code to help pin point the problem I'd start by checking those things first. Maybe try unplugging the mass airflow sensor and start it up and see if anything changes.

Did you use a gage and check proper fuel pressure? My info said 37--55 psi, so if it is about in the middle, it should be fine. Hope there is a Schrader valve on the fuel rail to check pressure?
How long since a tune-up? Any applicable trouble codes?
When you say it dies, are talking about idle? If so I'd check and clean idle air system. If you think there might be a maf problem? Some ford vehicles, engine off, just unplug the maf sensor, start it up and drive it, if it does better, check the maf sensor and wiring circuits.

You may have a bad TPS or throttle position switch. You might be able to borrow a fuel pressure gauge and check the pressure at idle. You can disconnect the TPS leads and put the Ohmmeter leads into the TPS(Not the truck harness}. The Ohms should change smoothly as the TPS is opened.

The Crankshaft position sensor is suppose to change the voltage to the fuel pump to increase pressure for the higher RPM. If the fuel pressure does not increase the engine will lean out and die.

While a bad cylinder can stall an engine at idle, most can run at higher RPM a cylinder short.

Scanners- You need a "check light" for the cheaper scanners to work. But a good scanner bypasses the onboard computer and allows the Technician to directly question the same sensors through the cars' wiring. Such that the outside scanner can do much more than the onboard computer.

Please rate my info.

Check the fuel pressure with a gauge. The pump may be going bad

the only way to tell for sure is to have the engine anylized with a real time scanner, it could be a sensor or actuator that is not throwing a code so a scan for codes will not help, if all seems to be od start looking for vacuum leaks, air bubbles in the fuel, fuel pressure constant, etc

check oil pressure sensor on strokers need a good oil pressure before they wold start and if they lose it , it would turn off the engine

If you have a check engine light on, than it is likely a sensor that needs to be replaced. If filter has been changed, you may have weak fuel pressure, or a bad sensor. A leaky fuel injector will also cause this

Check fuel pump for pressure and output. If it's not that, don't start guessing... have a scanner put on it and get some codes. While some codes can be ambiguous, it will serve to start you in the right direction!