I got a 94 Magna, 2.6L engine, engine model 4G54
car can not accelerate once last week and it happens several times after that. If I step on gas, engine starts to shake. I already changed spark plugs, fuel filter, air filter, but the problem continues.
I am thinking about checking the fuel pump. anybody has any idea where is the fuel pump relay located? And where is the connection point for pump pressure testing?

Have you tried replacing the spark leads?

I got a 94 Magna, 2.6L engine, engine model 4G54
car can not accelerate once last week and it happens several times after that. If I step on gas, engine starts to shake. I already changed spark plugs, fuel filter, air filter, but the problem continues.
I am thinking about checking the fuel pump. anybody has any idea where is the fuel pump relay located? And where is the connection point for pump pressure testing?

The shake under throttle open suggests an electrical high tension misfire. Look at plug leads, distributor cap, lead from coil to distributor, ignition coil, power transistor. Check electrical connection on distributor, MAF etc.
It's not likely to be fuel related. Fuel pumps either work or they don't.
But since you asked- relay connector is under kick panel under glove box, actual relay is attached to the rail that runs along the bottom of the glove box.
Pressure test - need a gauge and adapter, which goes onto the fuel rail or onto the fuel filter, depending on what adapter you have/get.

The shake under throttle open suggests an electrical high tension misfire. Look at plug leads, distributor cap, lead from coil to distributor, ignition coil, power transistor. Check electrical connection on distributor, MAF etc.
It's not likely to be fuel related. Fuel pumps either work or they don't.
But since you asked- relay connector is under kick panel under glove box, actual relay is attached to the rail that runs along the bottom of the glove box.
Pressure test - need a gauge and adapter, which goes onto the fuel rail or onto the fuel filter, depending on what adapter you have/get.

Thank both of you.
I am gonna check all these items you just mentioned.
I also suspect a brown head gasket since I overheated the engine months ago. Could that be a problem?

Have you tried replacing the spark leads?

replaced mine when i had same issues as the OP, and it fixed my problem.

Have you tried replacing the spark leads?

Thanks. Just changed one of my spark leads and the car seems ok now.