jheinz2

Just bought an 01 4.2 w/ 112k on it. Bought it with a 0130 - O2 bank 1 sensor 1, 0171 - bank 1 too lean, and an 0174 - bank 2 too lean. First weekend with it home, put the bank 1 upstream o2 sensor in it, along with an oil change, plugs, air filter, and injector cleaner. While changing all this, i found 2 hose problems, one small 1/8" vacuum line on top of valve cover driver side bank, and one back of engine large approx. 5/8" emissions hose. Not sure what this one is, thinking it's an EGR hose...? Anyway, fixed those then cleared codes, engine runs like crap. Get every cylinder misfire except for 1. Runs fine above 1k, drove around for 1 day, still runs crappy at 7-800 rpm but much better than day before. Today i still show 0171 and 0174 codes, also 0300 (random misfire), 0304 (cyl 4), 0308 (cyl 8), 0306 (cyl 6), 0303 (cyl 3) all misfire codes.

Then after grasping at straws, pulled the plug on the MAF sensor, started and ran great at idle. Before I order a new one, what do you guys think? Anything else I should check first? I was also going to grab a fuel filter along with my next order of parts. Read a handful of posts saying to clean MAF sensor, and fuel filter but that's about all I can find on these codes...