I have read and researched this website for two weekends, pulled codes, replaced parts and now I'm getting extremely frustrated.
Heres the problem. About a month ago my truck would start bogging down really bad after it warmed up good. Kind of like it was starving for air. Does it mostly when you are at low rpms such as taking off from a stop light or running 65mph in O/D and then needing to give it a little more gas to climb a hill. It will bog down to the point you literally have to floor it to get it to "open up" and take off.
When all this started the engine light started burning so I took it to an auto parts store and put it on the code reader. It showed the following codes:
Memory code 337
KOER: 172,173, 334,337
Removed the egr, cleaned the unit and made sure the tube from the exhaust is clear.
Checked EGR valve with vacuum pump and all checked out well
Replaced the EVP
Replaced the EVR (egr vacuum solenoid)
Removed and thoroughly cleaned the IAC( just for good measure)
Also should mention the oxygen sensor is only 2 months old
After doing all these the truck still had the same problem so I took it back and had the codes reread since the check engine light was on again. This time on all tests it showed me a 111. Yet as soon as I got away from there it started acting up again. Since it seemed like its almost starving for air when this happens I decided to unplug the mass air flow sensor and see what kind of result I would get. Now the truck would slightly hesitate but by no means completely bog down or even require extreme throttle change to make it go. Came back home and removed the MAF and cleaned it the best I could with throttle body cleaner and put it back. SAME PROBLEM.....then I blocked off the egr with a plate thinking maybe I was still missing something on the egr side of things.....no difference......i have spent quite a bit of time on this and I really need some kind of guidance. I figure everything is a cause and effect circle with this EFI system so first of all would the egr system cause the truck to starve itself for air thereby causing the bogging down and also causing the oxygen sensor to show lean and rich at different points? PLEASE HELP