P0171 Error and Fuel Injectors

OK..Here we go again. P0171 is reporting lean fuel mixture on Bank 1. New plugs, wires, MAS and Oxygen sensor have been replaced. After clearing error codes, P0171 appears after a few miles. I then purchased Seafoam and sprayed anout 1/3 of the can into the throttle body, the rest into the tank. Still no resolution. Presuming some injectors are clogged/dirty, what is the best (and cheapest) method of cleaning the injectors? Any ideas on service places to use and guesstimetes of prices..?

See my website for a diy injector cleaning.

PO171 can be caused by a variety of conditions, including:

1. Misrouted Oxygen sensor wiring contacting the exhaust system
2. Poor PCM to engine block grounds
3. Low fuel pressure or injector problems
4. Vacuum leaks at the throttle body, EGR valve, and intake manifold. Damaged or disconnected hoses, improperly installed or bad PCV Valve
5. Exhaust leaks in system, cracked or leaking exhaust manifold etc.
6. Mass Air Flow Sensor
7. Fuel Contamination by water or alcohol
8. Poor connections at the PCM or damaged wiring harness.
Good Luck!

Herc and Blackarrow,

Thanks for your help. I will selectively try and replace any of the lower cost items, PCV etc., and elimnate any of the items already replaced.