Ford Repair: 1993 Ford Econline van 150, engine 5.0L, automatic, ford econoline van, ford econoline

Question
Hello! I have a 1993 Ford Econoline Van 150, with the 302/5.0L V8 engine, automatic trans.
Runs perfect from cold start to warm.
Then starts backfiring under a load at 1/4 to full throttle, at the air cleaner. (But Idles find)  
When warmed up,I put my foot on the brake, put vechile in drive, step on the gas peddel, engine starts popping at the air cleaner, but idles find. When cold, runs like a new car, all kinds of power.
I've replaced Plugs, Wires, Dis.cap, Dis.rotor, Ing.module, TPS, Idle air control, and all the intake gaskets on the plentum.
I tested compression hot and cold 150psi, EGR, timing chain no slack,and all temperature sensors.
I unpluged and cleaned all electrical connectors, and ground connections.
I hope you can help me!
sincerely
Marlin
989-634-5803  

Answer
Backfiring through the intake means that fuel is being ignited inside of the intake manifold.  You should check ignition timing, crossed plug wires, induction between plug wires, or sticking valves.  If all of these items check out okay, your fuel injectors may be dirty and restricted, causing a lean-burn misfire.  Power clean your fuel injectors by connecting a pressurized can of injector cleaning solution to the fuel rail's service port and turn off the fuel.  The engine will run at idle on the cleaner for about 20 minutes.  This is the best way to clean fuel injectors without removing them.

I hope this helps,
Dave