Hi all, Heres my problem. My 2006 Silverado 5.3 has had a check engine light on for about 4 months now. I cant remember the codes but one was a MAF code and the other two were lean codes. I cleaned the MAF and cleared the codes. They came back. My truck started running very poor a month ago. It has a very hard time keeping speed going up hills. It runs fine at low rpms but once you put your foot in it it falls on its face. Thinking the MAF was the problem i pulled the one off my moms 03 tahoe (5.3) and tried it out. The light stayed off but the truck still ran like poo. I disconected the battery for a bit hopeing the fuel trim just needed to be reset but that didnt work either. So i know for sure my MAF needs to be replaced. To remedy the situation I am going to replace the Fuel Pump and filter, Coil Pack (s), Spark Plugs. Prolem is what would be my best bet of doing first? Any help would be appreciated.