Last week, I was doing a favor for a family member and drove an hour to a city, anyway, on the way back, I noticed a very slight loss of power, my top 1st gear redline speed dropped from 42 mph to 40, it doesn't seem like much, but it felt, different you know? then the CEL came on and I checked the code, I believe it was P2096 Post Catalytic Fuel Trim Bank 1 System Too Lean. Looked it up and found the usual top answers were 1. The MAF should be cleaned, or 2. I need a new O2 sensor. Three drive less days later, I return to my car and start it. To my surprise, the CEL cleared itself, but I still felt the slight loss of power. Anyone have any idea as to what is going on?

 

Likely the MAF got fouled briefly, throwing off the fuel trims far enough to get the code, then it shed whatever the fouling medium was enough for the fuel trims to get back within range for the CEL to drop. You probably still have LTFTs that are REALLY rich from that, which would cause some power loss.

I'd clean the MAF, clean the ESS, reset the nvram and fuel trims to clear that false rich condition, and monitor the trims to make sure they are re-learning within range.

 

Clean your MAF. That reminds me that I need to clean mine since I have a long trip coming up over this coming weekend.