So my 2000 4runner has randomly decided it didn't want to accelerate normally. It takes forever to get to a decent speed and it rpms 2000 or higher til i do get to said speed then it lowers rpms.
Took it to a car part shop to find out its giving me the Lean code and shaft speed sensor or something another.
I have cleaned the MAF but it still does it.
It doesn't skip or jerk, but now i do notice a sound like hissing (air escaping maybe?) its louder when i try to accelerate and quieter when i'm coasting or going the speed limit...
Any ideas on what could be the problem?

 

Could be a couple things:

1. Hissing is a vacuum leak. Check all your intake hoses and open ports.
How did you clean the MAF and did the sensor wires come back silver afterwards? Or still light brown? Still dirty if its the latter.

2. What was the other code? Shaft speed sensor leads me to guess something transmission related. Auto trans huh? Be good to know the specific code...

More story to help you out. Like what was done prior to onset. And driving conditions when it happened.