dmbg

I recently bought a 2000 silverado 1500 4.8l. I am getting a 171 and 174 code. I tried replacing the MAF sensor and the codes still came back. being new to owning a chevy I don't know the "common" problems. The codes pretty much say running lean or fuel pressure problems. The spark plugs look fine (good color) Is there somthing that goes bad on most chevys or do I just start replacing fuel system components until it is fixed. Thanks a lot for your help.

in2pro

have you checked the fuel pressure? This would be a good place to start and would help eliminate fuel pressure or blockage as the problem since you have already service the MAF sensor
Also check for vacuum leaks, here is a you tube on checking for the leak
How To Find A Vacuum Leak - YouTube

EinST

Also, some aftermarket CAI plumbing changes the diameter of the air passages too much (just at the point the MAF sensor measures air flow which is what matters). The net effect is unmetered air or simulated air leak.

dmbg

thanks for the things to look into. I appreciate it. also I forgot to add some symptoms in my first post. when I first start the truck it idles at around 500 rpm, while idling it will go from 700 down to 300. once the truck reaches operating temp. this problem will lessen but not completely go away. also I dont know if this is a factor or not, but I am from WI and the past couple days have been the coldest of the year so far.