The engine is turning over just not firing. When I first began having problems starting the truck it would take 3 or 4 tries and became worse over time and as the weather cooled down into the 50's. I replaced the plugs, plug wires, cap and rotor before I really started any troubleshooting. So those aren't the problem. I can hear the fuel pump coming on for the 2-3 seconds like normal and I did have the fuel pump replace about 2 years ago. I then checked for spark and there is a spark, although it's a yellow spark not blue. Is that normal or is that a weak spark? Next I sprayed a little starting fluid in the intake and the engine fired on the first try and remains running but idles really rough and backfires occassionally. Also the truck started (without starting fluid) again after I shut it off, perhaps being warmed up helped.

So what do I try next?

Thanks.

 

I would start by checking for the correct fuel pressure, the fuel pump may be running but not delivering / holding the correct pressure. Check either the shrader valve or inline somewhere. The pressure should be 60-66 psi (415-455 kPa). I know the pump was only replaced 2 years, but its a simple check and could help determine where to go next.