I invested in a CIS fuel pressure tester, its around 80 bucks if you shop around. There are a number of tests you can perform to help pinpoint the problem. Your fuel system needs to maintain pressure for 1/2 hour after shutdown to be within specs. Without knowing for sure you might be replacing parts that are still OK.

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1985 380SE Blue/Blue - 230,000 miles
2012 Subaru Forester 5-speed
2005 Toyota Sienna
2004 Chrysler Sebring convertible
1999 Toyota Tacoma