I have 2005 Toyota Camry V6 and I have two codes for p0171 and p0174. It seems the short term fuel trim goes up as I press the brake pedal while the engine is running. When I smoked the engine, I didn't find any leak. It does sink a little bit and when it is cold and I drive it, it does feel like it want to stall out and shake like crazy on the road and once it warms up, it doesn't shake at all. Long term fuel trim is always at 32 percent and the short term fuel trim does bounce a little bit and goes up when I press the brake. I changed the MAF sensor and cleaned the throttle body and changed air filter and it still does the same. I'm starting to think it is the hoses from the brake booster or the booster itself. What do you think?
I forgot to mention, but I do hear a hissing sound when i press the brake pedal.
I did check the maf sensor and it is working fine and made sure I replace it with the new OEM sensor.
https://photos.app.goo.gl/bCYhTutd3aphpwBx9
Of course a brake booster can cause a vacuum leak. I've seen them fail to the point where the engine won't even run because the leak is so bad.
You obviously have a problem with mixture being too lean given a LTFT that high. There are a number of potential causes other than vacuum leaks.
Did you check MAF sensor operation before you replaced it? Is the new sensor OEM? (The Chinese knockoffs usually don't work properly.)
I have 2005 Toyota Camry V6 and I have two codes for p0171 and p0174. It seems the short term fuel trim goes up as I press the brake pedal while the engine is running. When I smoked the engine, I didn't find any leak. It does sink a little bit and when it is cold and I drive it, it does feel like it want to stall out and shake like crazy on the road and once it warms up, it doesn't shake at all. Long term fuel trim is always at 32 percent and the short term fuel trim does bounce a little bit and goes up when I press the brake. I changed the MAF sensor and cleaned the throttle body and changed air filter and it still does the same. I'm starting to think it is the hoses from the brake booster or the booster itself. What do you think?
If the engine is fine when you're not pressing on the brakes, and it struggles on the brakes, that's a classic sign of a significant vacuum leak. The booster takes vacuum from the engine to enhance the pressure of your foot when you stop. If you've never changed vacuum hoses, do those, first. If it still does it afterwards, replace the brake booster.
