sounds odd but i have the same problem on bank 1

after awhile at idle my LTB1 goes straight to 25 and the LTB2 is fine

 

so i'm not the only one. mine does the same thing and its pissing me off. what injectors do you have?

 

How low are you taking the offset and min pulse when this happens? If I take mine low enough mine will do the same thing. The injectors start misfireing and it goes WAY lean. My offset is around .49 in the 14v column and my min pulse is I believe 1.1 however the Siemens also respond different then the 50lb Who makes your injectors? Are you sure all your injectors are seated properly and its not sucking air around one on that bank? Just brainstorming here.

 

keep in mind that when it misfires the o2 will pick up the unburnt air in the exhaust, even if it is a rich misfire. a oxygen sensor ONLY reads AIR, not fuel. just something to keep in mind while you are fighting this. also make sure your plugs and wires are good.

 

injectors are delphi. from the research i have found these injectors aren't exactly compatible with the ls1 pcm's but people have made them work. i didn't know his till after i bought them. so with that being said, what is a good way to check for a vacuum leak around the injectors? it makes since because at wot both O2's seem to agree and at wot there is no vacuum in the manifold. if i take the offset any much lower than it is it starts going lean and you can feel it shake and miss here and there. i tried someones tune from hptuners from the 60lb injector thread and it was way lean and would bearly idle. i can try something if you want me to and i'l log it and post it up. i'm up for about anything at this point.

 

i thought maybe plugs and wires too. buuutt i drove the tahoe to a friends house with no bugs, jerks, or jiggles and all i did was swap injectors. i can feel each injector ticking away so i know they all have power getting to them. need a good way to check for tiny vacuum leaks at the injectors.

 

spray them with carb spray and listen for a change. if you hit one with a vaccum leak it will stumble. you can do the same to check intake gaskets. propane works also.

 

i'll try that. here are some logs.

 

so i put my hand over the throtle body after the eng was warm and i got 3 to 4 nice sqeals on the driver side before the motor died. here is a log. note toward the end when i put my hand over the TB the left bank stayed lean while the right bank went rich. i did it twice on the log.

 

so what was the end result?