I have a 1991 Dodge Shadow ES Convertible with 2.5 Turbo and 114,000 miles on the clock. The fuel system is original. I encountered a drivability problem where, if I mash the throttle, it will start to accelerate to a point, then buck and snort like it is starved for fuel. Back off of the throttle and is runs just fine. Normal driving and acceleration shows no problems.
My Haynes manual states that I should have 55 psi fuel pressure at the fuel rail. I put a test gauge at the fuel rail and measured 50 psi. I put the test gauge between the pump and fuel filter and measured 55 psi. I replaced the fuel filter on general principle. Again, I measured 50 psi at the fuel rail. When I increase the engine speed, the pressure will spike up to 55 psi then fall back to 50 psi.
I then installed a new fuel pressure regulator, an after market unit. I started the car and measured 48 psi at the fuel rail. That didn't seem to help, so I put the old one back on. Now it is back to 50 psi at the fuel rail.
The Haynes manual isn't that helpful beyond that. Could it be that both my original and after market replacement pressure regulators are both not up to par, or is there something else I am missing. And what about my fuel pump? Does the output pressure at the inlet of the fuel filter seem reasonable or is there something I am missing? Any insight into this situation would be greatly appreciated.