Der, wrong choice of words. Was intending to insinuate that I will end up having to check everything to find the problem and it won't be until I am at the very last thing it could be to find the issue.

Isn't it some kind of sarcastic law? Kind of like having to check a 100 Christmas light strand for a bad bulb and it's always the 100th bulb. And yes it is a great thing that newer strands of lights do not always have that issue.

 

The codes are the only way the system has of telling there is a problem.
The codes do not tell you what to replace.
For example the code 171 is for bank 1.
It tells you the software table in the computer cannot correct for an air/fuel fault in the hardware that affects the whole operation.
Faults are; to much 'unaccounted' for air.
To much fuel for some reason.
The OX senor for bank 1 is the final reporting point.
You need to investigate the above possibilities.
Think Auto Zone knows how every make modle and year works?
Don't think so. They doen't pay enough to higher that level of employee that could make better money in a shop.
At least here, it's free and more accurate.
Good luck.

 

That is exactly why I said that I am going to investigate every possibility.

 

I had p0171, p0174 not long ago and was the elbow just past throttle body under IAC. That plastic line it connects to runs back to passenger side rear valve cover pvc and splits to back of intake with another elbow there which was busted for me too.
Squeeze that elbow under IAC and if you hear difference you got it. I could hear clearly air near firewall when shutting the engine off. If one of the elbows is bad you might as well change both. The whole setup front to back plus pvc was $40 for me from dealer.

 

Hey anealm, thanks for the tip, I am going to go check that out here in a few minutes.

 

my 2 Cents. 171 and 174 are hardly ever the o2 sensors. thye are the o2 sensor doing there job. a lean condition could be a vacuum leak, bad manifild gaskets, fuel pressure problem. .........misfires can be caused by a lot of things.........your 3 codes could be caused by a fuel pressure problem......I bought a codereader at Costcos for $20..........if .this was my truck this is what I would do.. I would do a tuneup, plugs. wires/cops, air filter, pcv, fuel filter(this could be your problem), clean TB and Maf........I would look for broken vacuum lines......if the codes were there after the tuneup, I would suspect maf, i would do a fuel pressure test if possible.

 

I changed the gaskets on both the upper intake manifold and plenum. Cleaned them out really good while I had them out to, they were covered in grit/carbon. I also cleaned the Mass Air Flow sensor with MAF cleaner. Another problem I found was one of the lines coming out of the back of the plenum had a large hole in it, leaking anti-freeze all over the back of the engine. I made sure to replace it.

Since then that truck has been running much much better, still have a slight idle problem, kind of stumbles around while it's speeding up. So I am 99% sure that I will be buying a new Mass Air Flow sensor. I have my fingers crossed that it will solve the last of the issues I am having.

I will also be changing out the plugs and wires while I swap out the MAF.