Hey all...

I've got a 2004 Tahoe 5.3 @ 173k
-212/218 low lift cam/z06 blue springs
-BB Tune
-CAI
-LTs
-Shitty flowmaster super 10

Anyways, cruising at highway speeds my fuel trims seem to be okay and close to zero. But every now and then the PCM pulls up to -9% on the LTFT. Sometimes if I blip the throttle off idle at a stoplight it'll jump to +13% then immediately back to normal. O2 sensor voltages are usually close to .9v both sides. They are **** bosch sensors.

At idle it's a constant -7% LTFT both banks.... Doesn't change unless I hit the throttle a bit. Any ideas what could be causing this?

 

Most likely the tune is a little off. I am guessing this is a mail order tune? Your pcm is adjusting as needed. Do you have a wideband? It's not s big deal, but basically its a tad rich in the idle tuning so it's compensating. 7% is quite a bit so I really doubt it's the cold winter air casing the rich condition.

 

Correct, mail order tune.

I've gotta take my intake manifold off to clean the huge amounts of carbon/oil buildup out of the runners, etc. Any easy way to tell if injectors may be clogged? Only reason I ask is because the LTFTs sometimes go to -7% cruising and my wideband gauge will read anywhere from 12.5-13.5 for about 15 seconds or so at highway cruising speed.

And it's only getting 12mpg highway on flat ground no wind. I know my level kit and 285s don't help but 12mpg seems too low.

 

you have a cammed 53 on 285s in a tahoe. that mpg really isnt that bad with all things going on

 

Well I pulled my intake and throttle body to clean them both. Throttle body was gunked up pretty bad and the intake had large amounts of buildup. Is it normal for that build up to feel as tough as bed liner?

Injectors looked spotless and the FPR vacuum hose had no fuel in it that I could see, but definitely smelled of fuel. Should I go ahead and replace that or is that fine?