I thought I would post this as it may help someone out. I have been fighting these two codes on and off for about two years. It seemed like every time it gets below 60 degrees out, the truck would throw these codes. I live in Houston, so it wasn't a big deal. I'd clean the MAF sensor, pour a bottle of Seafoam in it and clear the codes with my scan tool and be on my way for a couple of months.

Over the last few months, it got to where the CEL would come back on almost immediately, and the fact that it is summer, I figured I need to address it. I figured it was probably the injectors since they have never been changed and the engine has 270K miles on it. I have changed everything else out on it over the past couple of years that could possibly affect it, so I figured this must be the last thing I could do.

While ordering parts to rebuild the injectors, I decided to order a new brake booster since it was making a leaking noise that has progressively gotten worse over the last two years. Now I've read where vacuum leaks can lead to these codes, but I checked everything under the hood and never found any leaks. I never put two and two together that it may be the brake booster that was contributing to the problem.

Well, I replaced the booster about a month ago and have not had the codes return! I still plan on rebuilding the injectors, but now I can wait until the fall when it gets cooler and not have to worry about getting it to pass inspection next month!

Just thought this may help someone in the same predicament.

 

Great find. Thanks for the feedback!