My 2002 Subaru Outback (4 cly,auto, 150K) surges and stalls repeatedly when the car coasts down to about 40 mph. Sometimes does it on takeoff from a stop light also.
When was the last time that you had the spark plugs, air filter, and fuel filter replaced?
How long has the Check Engine Light been lit up?
You might have a point with the plugs. YOu don’t replace the fuel filter on these usually, it is a presurized system with a long-lived (I hesitate to say perminant) filter. New air filter every 12,000 mi. Check Engine Light is not on.
Let me suggest you look at the owner’s manual recommended maintenance schdeule and bring all the overdue maintenance up to date. I suspect there’ll be more than the plugs that need changing. And I’d be surprised if the fuel filter wasn’t among the items.
All fuel systems are pressurized. That does not mean the filters don’t need to be changed. It just means the system needs to be depressurized before doing so. The procedure to do so will be in the $20 Haynes manual available at the parts store. I recommend picking one up.
“YOu don’t replace the fuel filter on these usually, it is a presurized system with a long-lived (I hesitate to say perminant) filter.”
I beg to differ. Subaru recommends that the fuel filter be replaced at 30k, 60k, and 90k, and specifies that it should be replaced at 120k. (If you don’t believe me, open up the Warranty and Maintenance booklet that should be sitting in your glove compartment)
So, even by the most generous (negligent) interpretation of the manufacturer’s maintenance schedule, you are now 30k overdue for a fuel filter change. Deferring services like this is extremely short-sighted because, in addition to likely driveability problems, you are shortening the life of your fuel pump by forcing it to pump through a nearly clogged filter. Truthfully, only the well-known longevity of Subaru fuel pumps has prevented failure of this component so far. On many other makes you would have replaced the fuel pump long ago.
I would suggest that you take a careful look at the Subaru maintenance schedule because there could well be other vital services that you have skipped, in addition to the fuel filter. Cheaping out on maintenance tends to be more costly in the long run, as compared with timely maintenance.