right now my air fuel ratio is set to around 12.8 at idle..so today i was jump startin some guys truck and i let my truck idle for a quite a while and then it started backfiring really bad when i drove off..so i get back to work and pull some plugs and they are really black..so i put in a new set and later on today i was doing a lot of idle tuning since i gotta new iac motor and got every thing done and went and drove off and it started crapping out pretty bad again..think my plugs are fouled??

 

Mine idles between 14.5 and 15.2 when warm, On a cold start it will be at about 12.8-13.5 until it warms a little.

Lean it out a bit and clean up the plugs.

 

Mine idles at 14.6-14.7 when warm and 13.5-14. when cold. I would lean your idle a decent amount. Thats too much fuel for idle.

 

the only reason why i set it that low and that it would idle great and in and out of gear was good..but ill lean it out to 13.5 or so