Check engine light!!

[In2deep]

Well i decided since it was time to put gas i would put a fuel system cleaner- octane booster, after doing so the engine revved funny and the check engine light came on, the tuner reads system running lean any ideas????

[slick-svt]

Did you fill it up when you added the fuel-octane cleaner??

[tiffo60]

I'm guessing its just jacking with the o2 sensor readings, drive easy thru that tank of gas, and when you refill maybe it wont throw anymore codes

[In2deep]

Yeah i added the octane boost-fuel line cleaner first, then i filled it up.. Even before pulling out of the shell the sel came on, i drove straight home hooked it up and it said bank 1 running lean, reset code drove around the block came back on ,then i went on a straight away, i wot the truck pulled over after the codes where bank 1 and 2 where running lean, cleared them drove around another 15 minutes the light did not come back on???

[L8 APEX]

All Ford's throw 174 171, just ignore them. Or Google it if you get bored. It is usually a rotten vac line under the intake.

[In2deep]

Replaced the vac line was not rotten, you think the carbon build up clogged the o2 sensors??