Look at this stuff first before you buy any more parts
My usual No Start -
WTS Light? - do you get it when you first roll-on the key? (shows the computer is running)
Do you see cranking rpm on the Tach? Do you have a spare CPS to try? (here you should have posted the yr of your truck it May/May Not show cranking rpm)
Is there fuel in the fuel bowl now? Does it refill after cranking? (open the drain lever to check) Look above the pass ft tire, you'll see a 3/8" metal tube, against the motor that ends there, it's the drain for the bowl (yellow lever you slide to the side). Get a cup, open the lever, drain the fuel bowl, look at the fuel, close the lever. Then, turn the key to the ON position (should hear the pump) for 15 secs. Drain the fuel bowl again, whaddya got?
Can you hear/feel the pump running (below the dr seat, against the framerail)
Could the fuel gauge be giving a bad reading? (Below 1/4 tank?)
Is it cranking fast enough? - it won't even TRY to start if cranking too slowly.
Is your truck "chipped"? If so, remove it as a Test.
You can unplug the ICP sensor, as a Test, so the PCM sets a default value for the IPR to run on (expect this to set a new "Low ICP" code, don't let that misdirect you after a scan).
Did you check the plug and sheet metal nut going to the IPR? That nut can vibrate off and allow the solenoid going over the valve to slide around. The wires going to the IPR can get brittle, crack, and short together. Make sure the plug & wires look in good shape.
*** On the some '01s and all Earlier -If you Do NOT have a trans temp gauge in the instrument cluster (means you have an "early '01" w/o the electrical upgrade) then you should see cranking rpm on the tach as you crank it on the starter (means the CPS is doing it's job)