Subaru Legacy fuel system problem?

I have a 1991 Subaru Legacy AWD wagon. It is a right hand drive, has about 245,000 miles on it and I use it to deliver mail, so it is really important to me that I keep it running as long as I can.



Anyway, there seems to be a problem with it that still has my mechanic somewhat stumped.



When I am accelerating, usually up a hill or trying to get up to 55mph so that I am asking for at least 3000rpm, the car will usually get up to 40mph or so, then the rpm’s drop off drastically, the engine starts knocking and it’s almost like there’s something alive under the hood if I keep my foot on the gas. So I take my foot off the gas and sometimes it will keep running–sometimes it won’t and it will stall. Worst case I have to sit for at least a couple of minutes and pump the gas a couple of times before I try starting it again–and it has to crank for awhile before it finally does start. It’s like there is no fuel for it to start with. The most recent time this happened I noticed the little green ‘Power’ light on the dash blinked and I think I counted 13 times (my mechanic has been unable to find the computer code for this).



My mechanic has cleaned the fuel injectors once and changed to new ones once. The fuel filter has been changed twice within a 12 to 14 month period and my mechanic says this car has one of the filthiest fuel systems he has seen.



The car has been doing kind of OK since the last fuel filter and injector change, but it’s starting to act up again and I think it’s been only about 7-8 months since my mechanic did the last work on it.





I’m fishing for some ideas here so that I can keep my mail delivery car going!



Thanks for any ideas!

Have your mechanic check for a restricted catalytic converter by performing an exhaust back-pressure test.

Tester

Thank you for the idea. I will bring that up to him. I have replaced the catalytic converter once so it is not unlikely that it could need a new one.