Does anyone know? Has anyone had their a/f ratio measured in bone stock trim? I had mine taken today at the local performance shop with a wide band tester and it was 14.5 at cruise, which is fine, and from 13.15 to 12.90 at WOT which is LEAN!!! (FYI, had a bung welded before the pre-cat near the first O2 sensor for the a/f meter probe). I had these taken while in stock trim (except for the Denso I20's). What tipped me off are the very high EGT readings I get at WOT (1500 deg F on #5, 1600 deg F on # 3). Took it to dealer last week to check out fuel delivery, MAF, etc., they found nothing wrong. Armed with these a/f ratios, went back to dealer - am expecting another run-around. Otherwise, the truck runs very strong, I don't think it is a fuel pump problem.

Have heard that stock a/f ratios on L's are pig rich, very high 9's or low 10's? Any opinions or experiences?

Thanks Guys

 

99-00 are approx 10.0-10.5
01 are approx 11.5
Not sure about 02.......but I would assume they are the same as 01's

--Joe

 

Joe is corrrect on a stock 99-00 L the air-fuel is much richer and on the 01-02 L's the air-fuel is around 11.5-12.0 depending on the truck and your dynoshop.

 

Thanks soap and HIGH ROLLER,
Ok, so I am a point and a half too high on a/f ratio. Truck is currently at the dealer for this, but I am not expecting much from them. Also called SVT, and they were no help.

What the hell can be wrong?