4agze Running Lean.

[shazeal]

For a while now the car has had idle problems but lately the engine seems to shudder quite alot. I pulled the spark plugs today and they are white, last time I checked a few weeks ago they were more of a grey/black colour.

I checked the O2 sensor output and idling at 2500 it puts out around 3-4v and any throttle puts it right upto 5v and it stays there. 5v being lean afaik.

There are no vacuum leaks, unplugging the tube running to the fuel pressure regulator and plugging off where it ran to actually makes the car idle higher and seems to eliminate the shudder.

Testing the fuel pump using the diagnostics panel, the pump just seems to hum along no werid noises.

Ive tested all the EFI stuff, due to another issue that came up and everything was fine.

So I am kinda guessing it might be the FPR is stuffed and not providing enough pressure?