Ford: E150 Acceleration Problems 5.0 86 FI, last ditch effort, acceleration problems

Question
Hi Ragu,
We have been troubleshooting this problem now for over a week. The van is Fuel Inj. 5.0 1986 (july '85)My husband is the mechanic, so please excuse some of my explainations.
In park and neutral it shows no problems. on the road accelerating, from a stopped or slow roll, it hessitates, sometimes stalls. When we atart the vehicle again, the problem is gone for only a few seconds, then it starts again.
We have changed the following, all these were necessary, timing chain, rotor and cap, ignition plate on the distributor, Map sensor. The problem continued, we found a bolt on the intake manifold had rusted and broken causing a vaccuum leak, we changed that., we have searched every vaccuum line on the van and vound no leaks. we checked the egr valve, and switches(?)in the passenger fenderwell (hooked to vaccuum lines. these were fine. still surges/hessitates. We changed the half moon shaped thing in the distributor, as a last ditch effort...... nothing...

We are at our wits end. The customer is waiting, we are out of ideas, we are now checking backpressure on the catalytic converter, after this....... ?????
Please, any ideas?? Please o please, you will have a place in my heart forever....... grovel grovel....
If you want I can call,

Peace, and thank you in advance, jeanie

Answer
Jeanie lets go back to the basic what do the spark plugs look like , fuel pump psi test should be 32-35 and vac unplug 40 -45.. ck the fuel filter it  the # 1 problem with a lot of slall concerns. I just had one in the shop last week with the same problem and it was the coil wire when we removed it the end on the dist was fine but the end on the coil was shot replace the coil and the wires solve the problem  .If these ck out let me know and i will send you a step by step pinpoint test.