1985 Volvo 740 • 300,000 miles

My car is A 1985 Volvo 740 GLE, Non turbo, 4 cylinder car. When I am driving, it acts as though it is losing fuel power to the engine and the RPM gauge fluctuates up and down as the car jerks with it the fluctuation. When I push the gas pedal down the problem used to stop. Now only when the car is cold does it not do it so much. But just today I was driving it and I tried to push the gas pedal down and the car sounded as though it was sputtering and it didn't want to go. I let off the gas completely and the car stopped sputtering and I drove the car home with a gentle foot. The gas is getting to the engine just fine but when I step on the gas it acts as though it wants to die. I don't understand what is going on with the car if it isn't the fuel pump? I have fuel injection as well so It couldn't be a carburetor problem. Please can you give me some good advice?
October 22, 2012.

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