2001 Ford F150 V8 Two Wheel Drive Automatic 190, 00 miles
Hi, I change my oil regularly with synthetic, the engine runs smooth although I still have the check engine light on. After running a computer diagnostic I changed the oxygen sensors, removed and cleaned out that exhaust manifold reroute line that recirculates hydrocarbons back to my intake section. I've changed my air filters and the computer still says oxygen sensors problem, running too rich I think was the last readout.
Lately, at idle, I get a rattling sound, upon accelerating it goes away. It also started making a loud rubbing sound when I turn on the heater fan as though some bearings are under friction. The sound appears to be more dominant on the lower left side of the engine when standing in front facing engine. Is this my water pump or a pump that runs off the engine and only engaged when I turn on the heater. I live in florida and this noise just started when I came north to Chicago and now I'm in the cold. Never heard this rattling before till lately, say the last week now.