[3.8Danny]

I recently checked my fuel pressure and it read 80 psi. With the ignition on it was reading 48 which is normal. It also doesn’t want to accelerate properly I’ve changed everything I could think of and still no codes. I’ve changed fuel pressure regulator, fuel filter, both upstream sensors, Maf sensor, tune up. I think I changed more but can’t remember. Any tips would help a lot.

 

[Injuneer]

If the fuel pressure is 80 PSI with the engine idling, the injectors are flowing about 25% more fuel than the PCM is programmed for. The PCM can only reduce fuel flow by a maximum of 23% based on O2 sensor feedback (using the long term fuel trims), so the engine is running excessively rich.

That will foul the spark plugs, causing misfires. All that extra fuel can bypass the piston rings, wash the oil off the cylinder walls, and dilute the oil in the crankcase to the point where the engine can suffer piston ring and bearing damage. Check your motor oil for the smell of gasoline. When you pulled the old spark plugs did they show signs of excessive carbon buildup?

The fuel PRESSURE is not affected by the O2 sensors, the MAF sensor or the condition of the plugs/wires. They can cause an excessive fuel FLOW through the injectors, but not excessive fuel pressure.

One possibility would be a restriction in the fuel return line from the fuel pressure regulator to the tank sending unit.

Odd that there are no codes set for exceeding the limitations of the long term fuel trims, but the short term fuel trims may be overriding the limits of the long term corrections.

 

[3.8Danny]

The first problem that popped up was a cylinder 2 misfire changed plugs and cables and the plugs had some carbon build up but nothing excessive.
It also shows bank 2 sensor 1 failed so I switched it out.

From there my accelerations issues started. I would floor the car and it wouldn’t move. You could just hear the fuel pump working. Going uphill it would stall. I was looking at old codes and it was all 02 sensor related. I’ve gotten three different opinions and none have no clue what it is or where to start.

 

[Injuneer]

So you feel my opinion regarding the possibility of a plugged fuel return line is not valid, and I “have no clue”? Interesting.

Have you measured the fuel pressure while driving the car? Or only at idle? Are you sure your pressure readings are accurate?