I'm having a problem with my Ranger, in which it's throwing the p0300, p0304, p0305, and p0306 codes. I'm wondering what could cause this? Maybe a clogged fuel rail? It ran fine, and then one day started doing this. It idles extremely rough, hunts, and stalls if I don't have my foot on the pedal. If anyone has any ideas that'd be great!

 

How many miles on your '97?
How long ago did this begin? Had someone worked on the truck?
All 3 cylinders on the engine's left side. Did you inspect the spark plug wires?

 

Just over 104k on it
this began a couple weeks ago, I parked it running fine and the next morning it did this.
I do all my own repairs
yes I did, we've narrowed it down to a fuel system problem. Waiting to get a kit to determine if it's pumpside or engineside.

I'm thinking it's a clogged rail, because when I stuff my foot into it and it gets above 3krpm it runs fine, but below about 2.5k it doesnt run on that entire bank.

If you've got any suggestions, id love to hear em. Were going to disconnect the fuel lines in the engine bay at the frame and check volumetric flow and make sure they're outputting the same volume there, that'll determine pump or rail.

Thanks!

 

Change your fuel pressure regulator