Volvo: Volvo 1988 240 Bucking, volvo 240, gas tank

Question
QUESTION: I have an 88 Volvo 240 and it has been bucking lately between 2nd and 4th gears.  I replaced the fuel pump in the gas tank when the problem first happened about 3 months ago.  Then about a month ago it started happening again so I changed all the spark plugs and it ran fine until this morning and the same problem is happening.  It feels like it is a lack of fuel because you can feel the car spudding like it is about to run out of gas but the tank is full.  Any ideas?

ANSWER: Dan,
Maybe the flow of fuel is not enough. I have had two that I needed to install the heavy duty pump. That is the one they use in the 700/900 turbo. To do so you need to shorten the tube of the sender.

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QUESTION: If it was the flow of fuel would it be happening all the time?  It only happens everyonce in a while not everytime I drive.  Thank you for the help!

Answer
Dan,
The cars that I experienced would buck when you would accelerate hard in first and second gear. I did not know what else to do so I tried the larger pump and that was the fix. I do not know for sure if the vehicles had any problems of bucking before the pump installation. The flow being a bit low under slow driving conditions might not be noticeable, but under acceleration it is.