2004 Grand Marquis P0193 code
 

I am on the verge of scrapping my car due to a code that no one can fix. I have a p0193 code, high input signal from the fuel rail pressure sensor.
I have tried two new fuel pumps, three different fuel filters, a new fuel pump relay, and two different fuel pressure sensors. The sensor and fuel filter are genuine motor craft I ordered through Parts Geek. I also changed out the fuel rail with the same part number fuel rail from a junk yard along with 8 new Motor craft fuel injectors ordered from rock auto. I did thoroughly clean the fuel fail before installation I also replaced the intake manifold with a ford performance one because the old one was starting to leak coolant. It is not the manifold either because I put the ford performance one on my 03-town car and have no issues with it. Someone tried to tell me that it was the ford performance intake manifold causing the problem. I have spent hours and many dollars trying to fix this problem with no success. At times the check engine light will go off for a while only to return and there is no consistent time frame or pattern of behavior associated with the light going off then coming back on. The other day I did a battery disconnect to clear the codes and reconnected the battery, the check engine light went away for 220 miles of driving of which I started off with a full tank of gas. After work I started the car to go home at that point I had about 3/8 of a tank of gas and the check engine light came back on, the other thing I noticed is a popping noise when I started the car, almost like a very small explosion type noise. I have had the car to two different mechanics, and they can't figure out the problem. My last resort is the Ford Dealer but that could easily be around 1500 dollars to check it out and no guarantee that they could fix the problem. I use 85 octane fuel because we are in the Rocky Mountains and do not need a high-octane fuel here due to the altitude being close to 4700 feet. Any advice just might help, I have my emissions test coming soon and if it doesn't pass, I can't legally drive the car. Fuel pressure was checked and the mechanic said it was okay, I also thoroughly cleaned the throttle body. Any advice is appreciated. Maybe a bad catalytic converter or contaminated fuel tank? I am not sure? Thanks.

I have an update , I had previously bought a Napa fuel filter when I changed the fuel pump and the check engine light had stayed on. I finally bought a genuine motor craft fuel filter and installed it and have now gone 900 miles with no check engine light with the P0193 code.since installing the motor craft fuel filter. If any of you get a P0193 code I highly suggest using only a Motorcraft fuel rail pressure sensor and a Motorcraft fuel filter.. There is no fuel pressure regulator on the Grand Marquis and it is a very sensitive system so it is my opinion that genuine ford parts with the fuel system are critical for proper operation of the vehicle. By the way the Napa fuel filter said ( made in China ) and the Motor Craft is ( made in the Usa ) This should tell you something about quality.

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