91Z 305 TPI.

symptoms: hard starting when cold, surging during accel from dead stop, barely any power at WOT, positive blms. Very low O2 voltage during WOT.

my diagnosis: fueling. Either pump, filter, FPR or injectors.

Questions: What psi should I have? What volume? Does the FPR come before or after the service port?

 

anybody?

 

Does anybody at least know what the fuel pressure is suppose to be???

 

Fuel pressure spec is 35-40 at idle with vacuum connected, 40-50 on throttle snap or with vacuum disconnected. Check for issues with your MAP sensor TPS, and CTS. MAP should read about 1.5 at idle and 4.5 WOT. TPS should be .5 at idle and 4.5 WOT. CTS should match dash temp gauge. I assume you have a scanner since you know your BLM, look closely at scan data. High BLM means the ECM is trying to compensate for a lean condition.

The FPR is after the service port, just before the return. Your problem may be fuel pressure or pump but more likely fuel management. Check for any intake air leaks. You may also have bad injectors, check resistance, should be 12-16 ohms each. Injectors are devided into two banks. Each bank should test at 3-4 ohms(12-16/4).