Im stumped trying to figure out what wrong. Everything runs fine until it hits closed loop and and then the car starts stumbling, cutting out when you rev it and missing until it eventually dies. Once the car dies, it wont immediately restart. I have to wait a few minutes and then it will restart. The car is a 2000 gt stick all stock. This all started after I changed out the fuel pump, any ideas as to what could be causing this?
Thanks

 

sounds like a fuel pump prob man

 

Any DTCs present?

Also you state that it runs fine "until it hits closed-loop", how does it run when hot and not in closed loop (fairly hard acceleration at more than 60% throttle)?

 

It runs fine until it hits about 160 and then the car starts missing and stumbling. I wish there was a dtc code, I left the car running for a while hoping it would get a code. Does the fuel computer change the pressure when warmed? It seems the pressure drops as soon as it gets warm

 

It should not, the PCM uses injector pulse width to enrichen the mix when cold. Are you monitoring the actual fuel pressure in the rail, or the f/p PID?

The real pressure should be 28-30psi with the engine idling (39-40psi minus the manifold vacuum in psi). The generic PID (mode 01, PID 0A) will always be 39-40psi at idle unless the fuel is very hot when the PCM can raise it to 50+psi.

 

Im kinda just assuming the pressure is dropping because i dont have a gauge, but after the engine dies I check the valve on the rail and it seems like the is very little or no pressure compared to when i just primed it

 

You need to monitor the fuel pressure to determine what is actually going on...

 

Thanks Ill have to get a gauge to monitor it

 

How are you monitoring the ECT? Does it ever rise above 160°? I am wondering if the ECT sensor is bad...

 

Note: I just edited the numbers in the fuel pressure post above, I had been working on my bike earlier and had 43psi normal pressure in my head--our cars run a normal pressure of 39-40 psi.