Po171 And Regular Gas

[flaco]

I have been using regular gas in my 99 LS400 for a while now, mainly due to the cost and the car runs really well, no knocking, very smooth, good pickup.

However recently the engine light came on and I found the Po171 problem. I know generally what that means and a few things that can be checked but the question here is:

Is this due to the use of low octane gas and will it harm anything else? There is also a strong smell from the exhaust. Car still runs smooth.

[billydpowell]

I have been running regular for years, no odors or problems.