Car running Lean, any advice?

[Koolblue]

So my '99 Grand Prix Gtp is showing a code for a P0171B "Bank 1 System too lean" I have searched multiple threads to figure out what a potential cause/fix for that may be. I have already replaced the MAF (due to a previous problem which is now fixed) but this code showed up a few weeks later. Any ideas?

[BoostedPontiac]

It could be a number of things from a vacuum leak to a faulty o2 sensor and even misfiring. I would replace all the vacuum lines and check the egr tube at the intake and the exhaust manifold. also use your scanner to check you iac and ltft. Check out the vacuum tee under the supercharger snout. They are notorious for breaking.

[digitaloutsider]

^^^^ Completely agree. 9 times out of 10, that code is due to a vacuum leak. Start your search there.