I have a 95 caprice lt1 motor how will can tell if i need fuel pump.my car cuts off when i drive it for while or i try to start it after i cut the car off and the engine light comes on and both fan come on

95 Does not, you'll have to drop the tank to get the fuel pump out, some people have been known to cut a hole by removing the backseat, I do not suggest this as it could cause fumes to come back through the car.

Oil pressure cut off switch ? It doesn't cut anything off , it's purposes is if the fuel pump relay doesn't work ,when the engine reaches 40 psi oil pressure ,contacts close inside supplying voltage to the fuel pump . Watch this video on Fuel Pump Electrical Circuits Description and Operation from Paul Danner . He is an automotive instructor at Rosedale tech . Fuel Pump Electrical Circuits Description and Operation

Wow...Try the EGR valve...Plugged catalytic converter

What is the fuel pressure reading? It should be at least 55 PSI.

Definately sounds like the fuel pump

Hello! are you using the harness for that year LT1? the fuel air mixture is controled by the Manifold Absolute Pressure (MAP) sensor, the Throttle Positioning (TPS) sensor and the Oxygen sensors...When you put your foot in it without O2 sensors there isn't any control over fuel/air mix and ignition advance if the MAP and TPS aren't connected...I'm assuming your using the LT1 ECM...Guru...saailer

I’m happy to help further over the phone at https://www.6ya.com/expert/david_6df67de3b14de867

SOUND LIKE FUEL PUMP FAILING.

Sell it

U have 2 seperate problems, the gas gauge issue is caused by a defective sending unit in the gas tank, the cutting out will require u take the car in and have the electronic engine control system tested for trouble codes. Does this car have the 5.7 L engine?

Try checking fuel pressure again with a guage on the fuel rail. If you still notice the pressure is low and you know the fuel pump is good, the fuel pressure regulator may be bad. Sometimes you can tell by unplugging the vacuum hose from it and if you see gas that means the diaphram is leaking. If everything checks out with the fuel system a bad EGR valve or EGR valve solenoid can cause cars to sort of stall under half throttle. Good luck and keep me posted. If you found this helpful please rate this solution.

Thanks - Tech101