Just picked this jewel up today and its got an intermittent starting problem doesnt matter hot or cold. Sometimes you can hit the key fires right off no issue next time it fires up immediately dies then about 10 cranking cycles later it will fire up and run fine. Untill you shut it off then repeat process. My question is where should i start im sure its a sensory issue maybe the cps or tps? The only cel code it throws is a o2 sensor and thats it

 

Before starting, turn key on, count to 3 then turn key off, repeat that 2 more times.
Then try to start
If engine starts every time this way then the fuel pumps check valve is leaking.
You have to replace the whole pump it isn't a separate piece.

For safety reasons the Fuel pump only runs for 2 seconds when key is turned on.
It won't start again until engine is running.

2 seconds is good for 10-15psi of fuel pressure.
2000 Ranger should have 60-70psi of pressure all the time, even after sitting for 3 months.

If check valve is leaking it can be intermittent.
Turning key on and off 3 times will get you at least 45psi of pressure if system was at 0psi, which is enough to start engine.

If pressure was down at 20psi and you started it, pressure would drop to 0psi when engine started so it would stall just after starting, because fuel pump didn't start up until engine did.
Computer can't monitor fuel pressure, so no code would show up for this.


Could also be IAC(idle air control) Valve, this is a valve operated by the computer to set idle, fuel injected engines can't use idles screws, no jets.
The IAC Valve is a mechanical valve so can get dirty and stick, but it is easy to clean.
To start an engine the IAC Valve must be open all the way to let air in.
Wandering idle(up and down) is the usually sign of dirty IAC Valve so this would be a long shot.


Clean MAF sensor, this should be done every two years as general maintenance

CPS(cam position sensor) can't cause a no start, neither can TPS(throttle position sensor)
Sensors rarely fail, 90% of the sensors DIYers replace were working fine, 50% of sensors replaced by pro mechanics were fine.

That being said I have read that a TPS sensor showing full 5 volts can cause a no start, but it would be a no start all the time, not intermittent.

What is the O2 sensor code number?
there are at least 15 of them, only 4 are actually about O2 sensor, the rest are about O2 sensor working fine and reporting a problem.

A code number means all the sensors are working, and one of the sensors is reporting a problem, a mechanical problem usually, so "don't shoot the messenger"

 

Finally got around to checking the truck back out i do believe it to be the check valve cycle the key a few times and it doesn't miss a beat haven't tested the pressure yet that will be this weekend hopefully