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Marty
Marty, Mercedes Technician
Category: Mercedes
Satisfied Customers: 53168
Experience:  Bosch Certified Master Tech. Over 35 years experience.
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I'm dead in the water. 2002 C240 2.6L V6, had 2 codes P0171

Customer Question

I'm dead in the water. 2002 C240 2.6L V6, had 2 codes P0171 & P0174, running too lean. The decision tree started w/ MAF sensor, changed. Then the O2 sensors, changed. Still running lean. Ran okay, then great, now right back to running horrible. First when I needed throttle, run starved of fuel, transmission wouldn't shift correctly, now it won't start at all. Any suggestions since it has the same error codes? Fuel pump ? Fuel pressure sensors...... Thanks Lu
Submitted: 1 year ago.
Category: Mercedes
Expert:  Marty replied 1 year ago.
Hi Lu, I'd be thinking either a bad fuel pump or a bad fuel filter. I'd replace the filter first and see if it makes any difference. You might also have a defective MAF. A fuel pressure test would also be a good test to see if the pump and/or filter was faulty.
Let me know what you find out.
Marty