power loss

[Tim62]

I have a 95 Legacy with the 2.2 engine. When it starts getting warm it starts bucking and carrying on. If I have to stop I have to put it in neutral and keep pumping the fuel feed to keep it running. I have replaced the coil pack, the plug wires and park plug. I changed the fuel filter also. Could it be the fuel pump the vehicle has 258,000 miles on it.

[doublechaz]

I could be. It could also be an exhaust leak closer to the engine than the front O2 sensor. It could be an O2 sensor. It could be a temperature sensor. It could be a large vacuum leak that changes geometry as you come to a stop and the engine mounts flex from loading up against the trans and the brakes. Do you get any check engine light solid or blinking during the problem? What is you MPG like?

 

In order to fix it without randomly replacing the whole car one part at a time you'll need more data about what the ECU thinks is going on. Is it lean bucking, or is it rich bucking? Is it lack of spark bucking? You really want to get a scan tool that can show live data from the computer. Do you know someone with such a tool? I have a basic live data one that will talk to a 95 if you are around north/central AZ.