99 SSEI EGR EVAP P1404 Problems
I really need some expert help on this for I am chasing a ghost in the machine (99 SSEI). Let me start off by stating what I have done. New plugs, wires, catalytic converter, techron fuel treatment, and a used EGR valve (that I tested with a 9V battery). I canít remember the original codes I was getting but it was for a bad catalytic converter (and it was bad) and for the evap system. Then all of a sudden I started getting P1404. I took the EGR valve off and the pintle was clogged with carbon so I replaced it with a used one I had. Now the only code I get is the P1404 and that code fluctuates between setting off the CEL, pending, and not at all. I have multiple times done the pintle reset procedure on the EGR valve but my problem is still there. This is what the car is doing, at first acceleration and at slow speeds around 40mph while in OD when I am just barely giving gas the car is sputtering and the vacuum boost fluctuates about 5 pounds. Sometimes when I am at idle and in park if I step on the brake and the boost will fluctuate the slightest bit as well. And I have always had trouble with back pressure on my fuel tank while filling up at certain stations. Basically the fuel pump would click off every $5-10. I am at the point where I am thinking about replacing the fuel pump, fuel limiter vent valve, and flashing the computer. Any help would be greatly appreciated.