Does the problem stop if the gas tank is full?

If so, pull the fuel pump and check the bottom sock.

If not, I suggest that you replace the ECT to be sure this is not temperature related.

You can also check the following things:
  • Fuel pressure
  • EGR system
  • PCV system
  • Static timing
  • Vacuum leaks

"Those who cannot remember the past are condemned to repeat it" -George Santayana