Engine codes

[jpac1]

I have done some searching and reading and I think that I know what to try next, but would like a second opinion. The codes that I am getting are p0171, p0174, and p0300. The first two are fuel is too lean in both banks and the third is a random missfire. Now, from reading in the forums the most likely cause of the p0300 code is with my ditributor, cap, rotor or wires. I have replaced the wires 10k ago so I will check the cap and rotor. With the other two codes I was reading that the area that you live in and the outside temp can affect the fuel mixture. It was -25 to -30 for the last week and that is when I started noticing the problem. My truck seems as if it is going to stall, but only when it is at idle, after it warms up to opperating temp it gets to the point where it is almost unnoticeable. I have changed my fuel filter and will clean my air filter. From what I could tell I have no vaccum leaks. Could my problem my fuel pump? I have had this problem for a little over a week now. What else could I try?

[maxwedge]

Lean mixture can be caused by low fuel pressure, air entering the engine unmetered, dirty maf, and more less common issues. Do you have a noticeable misfire, also a sticking egr can cause this. More important here, it is absolutely required to post the year and engine, this appears to be coming a chronic problem with recent postings!

[jpac1]

Sorry, I know better than that. It is a 2001 with the 5.3L engine. To me the misfire is not noticable. What is the best way to clean the MAF and the EGR?

[maxwedge]

Get electrical parts cleaner and clean the wire in the maf, carefully, pull the egr and clean any carbon on the pintle and seat. Vacuum leaks and low fuel pressure are the next steps.

[jpac1]

Just wanted to update my problem. I unpluged my MAF sensor and the problem stopped, so I went to the wreckers (thinking that I needed a new MAf) and got a new MAF, put it in and connected it and now have the same problem. Does this mean that I picked up a bad MAF sensor or should I be looking elseware for a solution to my problem? The missfire was caused by a bad plug. Anyone with any ideas about the MAF? Thanks.

[maxwedge]

By disconnecting the maf you put the pcm in back up or limp mode for the maf, this probably richened the mixture enough to mask the problem, review my earlier suggestions.