Of course, the old addage, it is either fuel management, ignition managment or air delivery.
An overlooked issue is cylinder compression. It can be lost when timing chain/belts wear out and timing gets so far out it causes detonation and other internal damage issues. Test compression. The rule of thumb is the compression should be no lower than 100 PSI and the highest compression cylinder and the lowest compression cylider should be within 74% of each other.
Check fuel pressure. Even though you have a new pump, the pressure reulator could be bad.
Those are the most evident and easy, but it looks like you have done so much, I have a wlk through tutorial that helps rule out issues. Since this is process of elimination, I think reading through thiswill help to shorten the list of possibilites.
Here is the link to paste into your brawser;
Look it through and tell me if it helps or is it is all things you have gone through.
I will get back with you ASAP when you respond.
Please consider a to help us answer more questions.
Wednesday, October 12th, 2011 AT 2:59 AM