Codes P0174 and P0171

tacogrint

Member
Having a minor (hopefully) issue with my 06 Prerunner TRD V6. Bought the truck May of 2019 with 124k miles, previous owners took meticulous care of this truck. Drove it up to Virginia and back with no problem at all this past fall. One day my check engine light comes on, with no noticeable change in how it runs/sounds/feels. Cleaned the air intake filter, took it to autozone and the codes read P0174 and P0171, both banks reading lean. Take it to a local reputable family-owned mechanic, he runs the sames codes...but says he's getting contradicting readings that they are showing too lean and too rich(?). Ultimately he found a deteriorated MAF Sensor o-ring, which was replaced and he cleaned the throttle body. The code was cleared and didn't return. After about one week of driving a maximum of 40 mph, I get on the highway...and it seemed as though as soon as I got up to 60mph the CEL comes back on....any thoughts?
 
Oxygen sensor, bad spark plug or catalytic converter could be dirty or getting bad. I run Chevron techron every 3000 miles or so. I use a elm 327 vehicle health monitor by nonda and it told me one bank was running lean or rich but it told me it could be do to those problems. I tried a bottle of cata clean and was amazed out how well in cleaned my upflow 02 sensors and hopefully it helped the rest. Always run 87 octane its what the they was designed for and is used more than any other octane rating in my opinion. I try to run Chevron gas if possible, amercian gas is generally added with fuel detergents and additives to keep carbon build up down an fuel system clean
 
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