Have a stock 87 GN with 90,000 miles. Car was running fine but then intermittently started falling on its face around 3000RPM and just not making power. Turbo will make a little boost but engine will not get over 3200RPM and engine makes some low popping sounds as it stumbles and dies. Now the problem is there constantly. The fuel pump was replaced with a new stock pump a few months ago and have put at least 500 miles on car since it went it. Since chasing this problem have replaced ECM, chip, MAF, coil and ignition module and no change.
Finally hooked up a fuel pressure gauge and when key turned half way pump comes on and gets to 40 psi but dies off to 10 psi in a few seconds. With car started at idle getting steady 30 psi. When revved to 2000-3000 RPM gets to around 45psi then drops back to 30 at idle. While at idle pulled fuel pressure regulator vacuum line and pressure jumped to around 40.
The rapid loss of pressure when key turned half way and steady low 30 psi at idle makes me think the fuel pressure regulator is bad. Am I on the right track or are there other things I should be considering??
Finally hooked up a fuel pressure gauge and when key turned half way pump comes on and gets to 40 psi but dies off to 10 psi in a few seconds. With car started at idle getting steady 30 psi. When revved to 2000-3000 RPM gets to around 45psi then drops back to 30 at idle. While at idle pulled fuel pressure regulator vacuum line and pressure jumped to around 40.
The rapid loss of pressure when key turned half way and steady low 30 psi at idle makes me think the fuel pressure regulator is bad. Am I on the right track or are there other things I should be considering??