Issues with "bogging down" and not accelerating

Lately my truck (2001 Tacoma prerunner) has had an issue, usually in the mornings but a few times during the day, where I will start my truck, put it in the drive and press the accelerator. The truck will then "bog" down and not accelerate but rather barely creep along. The truck will sometimes do this for 10-20 seconds or so, then pick up and go without any issues. Ive found it won't do it as bad if I start my truck and let is sit for a little while, but it still does it occasionally with this.

My check engine light is also on with the following codes:

p0171 - Bank 1 too lean
p0174 - Bank 2 too lean

I've researched this issue and mostly it comes back to MAF sensor, fuel filter, O2 sensors, etc. Ive taken my truck to a shop I trust that has completed good work before. They checked everything that could be throwing the codes and cannot find any issues with the truck with the sensors, filters, etc. They could not pinpoint the issue.

Has anyone had this issue before? Had any solutions? Suggestions?

Thanks. I appreciate any help.

 

Vacuum leak in the intake somewhere?
Did they check the TPS?

 

I don't remember what code my truck was throwing when I first bought it but I do remember it being a "too lean" code. It would fall on its face if I tried to really put my foot into the throttle. I changed fuel filter, fuel pump, and was getting ready to change the injectors and rails when a mechanic told me to try and change the MAF. I already had tried cleaning it with no luck, but as soon as I bolted the new one in, the truck ran like new. You might go get a new one from the autoparts store and put it in. If it doesn't work, take it back out and bring it back.

 

How cold has it been in the morning? I could back out of the garage in the morning and then when I got to the street and put it in drive it would just sit there or go really slow. It was the transmission fluid being old and cold. Went and had a transmission flush done at the dealership and now it's good as new. And I have a 2000 PreRunner.

 

Well I believe it ended up being the MAF sensor. One shop took a look at it and gave it the thumbs up. It still was acting up. Another shop only had it reading at 60 something percent before and after cleaning. A new sensor seems to have done the truck and I havent had any issues or burnoff smell anymore. Thanks for the input.