97 ford taurus with a 138,000 miles, 3.0 L motor. When starting up has bad hesitiation like the old carborated motors w/choke sticking or bad accelerator pump. Is worse when cold ,but has some hesitiation when accelerating all the time. Have ran codes, but showed no codes. Had fuel pump installed and that resulted in no change. Also had fuel injectors cleaned ,helped but problem still existes and after 3 months is getting worse again. Recently while working on trans. computer showed code for catalytic converter problem. This code never showed in the past. Could this be the problem? If not what do you suggest?