This is an unusual problem. I have searched for any similar problems with no success. My wife drives a 1995 Volvo 850 GLT 5 Speed Non-Turbo 5 Cyl. Whenever we fill the fuel tank the car runs very rough. No power, sputters on acceleration, you have to back off the pedal a little to get the car to go. It runs very rough and as we add miles the car runs a little smoother. By the time you reach about 50 miles the car runs smoother. It makes no difference whether it is hot or cold, or highway or city. All that matters is how full the tank is. If I tell her to just put halfa tank in then the car runs fine. The fuel pump was replaced a few years ago, and this problem has been going on for the last couple years. I have tried different brands of fuel and all different kinds of fuel system cleaners. The fuel brand and octane, and the different cleaners, made no difference. The check engine light does not come on during any of the rough riding and the car doesn't stall. It just won't get out of its own way. Thanks in advance for any help.

 

When was the last time you changed the fuel filter?

 

It was done within a few months of when the problem started

 

Does it change depending on what kind of gas you use?

 

Could it be the fuel tank vent/return line is clogged?

 

My first 850 ran like crap after a fillup but I was also having ignition wire issues. I found that if I just filled to the point that the pump clicked it eliminated the problem. Don't continue filling to the next round amount.

...Lee

 

What have you replaced outside that you have disclosed?