I have a 96 Ranger SC 4x4 with a 4.0, automatic, and 90k miles. I haven't run the truck for two years and just got it on the road again. I replaced the plugs, wires, and coil pack. I'm getting a P174 and 3 misfire codes, 303,304, and 306. It does a lot of backfiring as you drive and seems to be a little (but not much) better when the overdrive is off. I have put two cans of seafoam through the system with little change. I have a new fuel filter but can't get the old filter off yet. Where do I start looking next?

 

if its been sitting a while it may have housed a few critters. i would start by visually checking the wires for damage under the hood, critters can cause some serious damage if they start chewing on wires. also its a good idea to change youre plugs after you run sea foam though it. did you pull the air filter out an check it? make sure there are no nests in the air box or intake tube.

edit, did it run crappy before you did the plugs and wires?

 

Dry-gas
That fuel tank is full of condensation.
Also plan on pulling the injectors and cleaning them. Run the fuel pump with the injectors out for a bit to get any rust/deposits out of the fuel line.

 

I was getting the same codes before, that's why I quit running it. There are no signs of any critters (got a cat with a big appitite). I put a full can of seafoam in the tank, two thirds through the motor, and the rest in the oil. Air filter is good, and it pulls a steady 18" vacume at idle.