Engine vibrates at idle, code P0302

Hello,

I have the car listed above VIN 2 Flex fuel Engine. The car has a very slight vibration at idle but under load its very noticeable. The car finally gave me a P0302 code. I check the coil with my test light and the spark was jumping to it before I got the wire off of the coil. The wires and plugs are new, I tested the #2 wire resistance and got 10.8k ohms reading. Moving the wire showed no difference in its reading. I changed the spark plug, even doe it looked good as its hard for me to check due to its location. I could only listen to the fuel injectors and they all had the same chatter sound.

I ran some tests with the vacuum gauge and the only test that does not meet specs is it reads between 15 – 16 psi at idle. Further, I applied a ground to the EGR solenoid and the engine runs rough. I checked the EGR Valve with my vacuum gauge and it held a vacuum at -20 psi, I could also hear it close when I released the vacuum. I also checked the vacuum hoses from the intake manifold to the solenoids and fuel pressure sensor. Because I could not find the electrical diagram, I did not test the DPFE for the 4 volts when I applied the ground but switched it with the DPFE from the 2000 Ford Taurus VIN U that ran fine.

I was unable to compare the fuel pressure with the 2000 Ford Taurus due to the fuel inline connector being stuck and the 2003 does not have a Schrader valve on the rail nor the fuel pressure sensor. The inline fuel pressure before the fuel pressure sensor reads 17 psi which seems low but does not explain how the car can perform with no problems when on the highway. I changed the fuel filter but it made no difference.

The 2 concerns I have are with the inline fuel pressure 17 psi and the 15-16 psi vacuum reading when the vehicle is warm. Any additional test I can perform to isolate the problem would be greatly appreciated!

Sincerely,

Paul