1998 Ranger won't start

[james23912]

Hi, I have had this 98 Ranger 4x4 with 3.0 extra cab for 4 years, very happy , has been running fine, but went out the other day and it turns over and starts to catch for a second but does not, I can hear the fuel pump turning on and sprayed some start fluid in but does not do anything, not showing any codes, I changed the crankshaft sensor, nothing, I am looking at the cam sensor, but the Haynes manual is confusing, says in one place I can change only the sensor but also says sometimes must remove the assembly, so I am not sure how to proceed at this point. The only minor issue I have noticed is the oil pressure gauge sometimes dropping and going back up, but I was low on oil. I realize there are many possibilities and I might spend on things I don't need, but I have other vehicles so have time, prefer not to have to have it towed. Thanks
I live in US, must have hit Canada by accident, though I do get some French radio stations