Erratic Baja Acceleration

I have an '05 Subaru non-turbo Baja with a Man Trans that surges during light acceleration as if it running out of gas. The car runs smoothly at cruising speed. The car has approx. 89,000 miles.

When was the last time that the fuel filter was replaced?
It should have been replaced at 30k and at 60k, and it is coming up very soon for its third replacement.

If a new fuel filter doesn’t help, then you might think about cleaning the Mass Air Flow (MAF) sensor.
If you have installed one of those K & N air filters, it is especially possible that the MAF is fouled.

Thank you. I do have a K&N filter and will replace the fuel filter. Where is ths the MAF sensor located?

I was waiting for someone who knows your vehicle to respond with a specific location. What I can tell you (without knowing the car) is that MAFs are always located somewhere in the fresh air intake ductwork. Find a short segment of the duct with an electrical connector and wiring coming off it, and you’ve probably found the MAF.

Fuel filter on 2005+ Subaru is in tank and has no regular service interval. It is not simple anymore like the underhood version 2004 and prior which had a suggested 30k interval.