I have a 92 3.9 2wd.My #4 cylinder doesn't seem to be burning as it should.It wont burn the gas.I have plenty of compression and plenty of spark.There is gas getting into the cylinder.My question is,is it possible the injector isn't putting enough fuel into the cylinder? I'm going to pull the fuel rail and the #4 injector tomorrow to see what I can find but having no knowledge of injectors I'm not sure what I'm going to be looking for,lol.I have an idea as to test the power to the injector and the fuel coming out but have never had an issue with injectors and I do all my own mechanic work.My other question would be how to test the fuel pressure.The #4 cylinder is the only one I'm having an issue with...
Thank you..

 

Swap that injector to another cylinder and see if the problem follows it.

 

another way to tell if cylinder #4 is starving for fuel is by looking at the plug. If it's white, that means it's not getting enough fuel. As a rule of thumb, if you replace one injector, you need to replace them all.