I am finally getting around to setting my timing on my '85 4Runner 22RE and just wanted to know if I should leave it at the factory recommended 5 or advance it some due to altitude? I'm in Denver at 5k ft. Also, if I advance it do I need to run premium fuel? Right now it runs well, but rich, as black crap comes out the tail pipe.

Thanks for your help!!

 

You can play around with it by advancing the timing until the motor pings, then back it off.

 

i live in 7200elevation and the motor works better if you speed up the timing a little

 

also advance it 2 degrees and run it on regular gas and you should be fine