Have a 2003 Prerunner. Engine light came on a couple days ago. I took it to auto store to put on computer. The computer read a p0171 trouble code, which is System too Lean (Bank 1). I bought some cleaner to clean the MAF sensor, but engine light stayed on, so I bought a new sensor and replaced it. Light is still on. This whole time my truck is running fine, not sluggish nor missing. Any ideas??