2002 outback rapid power loss

[PToutback]

Hello,
2002 outback, rapid loss of power, like no fuel or all cylinders misfiring, no code being produced, RMPs bouncing up and down. Replaced coil, plugs, and wires to resolve a misfire condition with a code. Intermittently happening, typically when car has been on a longer trip, over 10 miles, usually under a load, no specific gear (automatic).

 

[Lou O.]

Congratulations on 22 years of ownership! Sounds like you are going into limp home mode. Stop by a reputable parts store and let them scan for any hidden codes which may not be throwing a light.

 

[Mark Monte]

This is usually the symptom of a fuel pump going bad, which will not normally cause a Diagnostic Trouble Code. If you want to Troubleshoot this problem yourself, you can get a pressure test kit on loan from an auto parts store like Autozone. It is also a good time to replace the fuel filter which can restrict the gas flow to the injectors. It is a good practice to keep the fuel tank above a 1/4 of a tank because an in-tank fuel pump needs the extra fuel for cooling the pump so it doesn't overheat. There might also be gunk in the gas tank that gets sucked up when fuel gets low. Under load is exactly the moment when the engine needs more fuel.
If you are lucky, replacing the fuel filter may be all you need to do.

 

[PToutback]

Thank you, I did replace the fuel filter after and since the problem started, I’ll take the advice on the pressure test kit. Appreciate your feed back.

 

[Mark Monte]

I bought my '02 Subaru Outback at an auto auction at the beginning of '24. The gas tank was on empty!
I was lucky to make it to the gas station.
I also want to mention ethanol in the gasoline can cause problems because it can absorb water, and water doesn't burn. I discovered a product called Star Tron Star Brite Fuel Treatment. I had an old Chevy truck with a carburetor. It would die at traffic lights and I thought it was the carbs fault, but then I added this special enzyme formula and it didn't die anymore and idled fine. The enzyme actually saved me from the work of rebuilding the carb. You might want to give it a try if you have any misfires..