Cam sensor?
 

My ranger gets to normal running temp aand after about 15 minutes starts to misfire like all hell. I can't drive it. I was wondering if anyone knew about the cam sensor or maybe the crank sensor?

Welcome to the forum

What year and what engine?

Engine can not start or run without steady Crank sensor pulse, so not the problem

Cam sensor can cause running problems and if failing CEL(check engine light) would come on FOR SURE, cam sensor pulse is compared to crank sensor pulse by the computer, if Cam sensor gets "flaky" then code is set and CEL comes on.

If any engine runs poorly after a few minutes driving could be clogged fuel filter or partially blocked exhaust system

Sensors rarely fail, but are often replaced by DIYers so grain of salt

Gasoline engines have run the same since 1901, computers and sensors make then more reliable, the problems engines suffer from haven't changed, in over 100 years.
Fuel
Spark
Compression
Thats what a cylinder needs to fire

If any engine runs OK at any time or temp, then compression is good, it can't change(unless it is a 2004-2006 3.0l Ranger engine)

So you are down to fuel and spark

It's a 94 4.0. This is great advice thank you very much. I'll grab a fuel filter and give it a try. That's about the only thing I have not tried. The cats were plugged so I cut them off and continue to have this issue

I'm no expert, but I've been looking into the cam sensors on the 3.0 a lot lately cause I think it's the cause of the squealing in my truck.

I found this great video with some in-depth diagnosis of a cam sensor that was lose enough that at high RPM it would make contact with the sensor and not send a signal which would result in the fuel injector not injecting until it got the next pulse.


So I don't think cam-sensor issues are all or nothing. You can certainly have issues that aren't bad enough to prevent the engine from starting. They may be intermittent enough to not even trigger a CEL.

It has to get to this point until a cam sensor code shows up.