Now What

[realbadniceguy]

pulling heat bank codes.
car feels being held back.
performance shop says im running lean. but don't work on ls1's.
gm runs ls1's lean from factory.
more mods the more leaner it becomes.
and the slower my 1/4 mile times get.
mods-- headers, programed,intake upgrades.

so now what?
1.fuel pump upgrade
2.fuel pressure regulator

[Street Lethal]

Did you clear the codes that were set after the install....?

pulling heat bank codes.
car feels being held back.
performance shop says im running lean. but don't work on ls1's.
gm runs ls1's lean from factory.
more mods the more leaner it becomes.
and the slower my 1/4 mile times get.
mods-- headers, programed,intake upgrades.

so now what?
1.fuel pump upgrade
2.fuel pressure regulator

[mrr23]

don't know of heat bank codes. can you list the codes?

[0rion]

ls1's come rich from the factory
what programmer are you running?
I would have to dig around and make sure but the O2 heater codes could be keeping you in open loop. Do you have a means to log the car to see where it's running or are you just guessing you're lean? I would say get a good tune in there and that'll fix your problems.