87 4.0 hard start when warm

Hi I have a 87 with a 4.0 that will start right up first thing in the morning, but after it warms up the only way I can get it to run is hold the gas to the floor, then it starts, it is like it is loading up. even after 3 to 4 hours it is still hard to start. I have changed the o2,cps,coolant temp sensor, fuel presure reg and air idle motor. plugs, cap, rotor, and wires. what else should i check? it is like it thinks it is cold all the time. thanks, Tim

Sounds like you could have a problem with your injectors. you may have one or two stuck open, which would load that cylinder with fuel and make it hard to start. Check you oil, does it smell like gas! THere are replacement injectors for the 4.0 that are #19's out of the Ford 5.0. I have those in my 89 and they work great! Go online or search for injectors-4.0ltr.
YOu can check your injectors by tie strapping the injector tot he fuel rail, then remove the rail, get 6 little cups and place each injector in a cup. cyle your key a couple times to get the fuel pressure up, but DON"T crank the engine!Let it sit for a minute or two, if you have a leaking injector, you will see it either gushing out, or dribling out. Even a small leak will cause serious problems.