Q: 1999 Ford Ranger 2.5L. #3 and #4 cylinders are not firing, #2 sometimes doesn't fire.
Engine is getting air and has good compression. Fuel pump is working and I installed a new fuel filter. The injectors all read the same resistance so I assume they are all functioning. My next guess is to check if the cylinders are receiving power. Also, it could be that the fuel pump is not providing enough pressure to the fuel rail. It is either that or something with the injectors not getting signaled by the computer.
My car has 106000 miles.
My car has a manual transmission.
You should first check the fuel pressure is within specification. Then check plugs are getting fire and then do a compression test on all 4 cylinders. If all this is normal then remove injectors to look for clogged injector inlet screens for trash in the system that builds up and clogs the injectors. Clean or replace injectors as needed and flush out fuel rail.
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