Just an FYI on a repair that I had done recently.

A little background, my car has 38,800 miles on it, and it has back fired gently since I bought it. Part of this was a bad spark plug (it never got any corrosion protection on the contact end which required me to clean it each oil change) that came from the factory, but when that finally got replaced at 35,000 miles, it didn't fully solve the problem. I had taken the car to the dealer several times in its life to try to correct the problem, but without a CEL, there wasn't anything that they could find.

The car still lagged on hard acceleration around 4,500 RPMs. At 38,800 the car threw a CEL for the first time in its life and power dropped off substantially especially after 4,500 RPMs. The codes were P0171, System too lean Bank 1 and P0410, injection pump fail.

I took it to the dealer who diagnosed it as a cracked intake manifold and particularly a broken T junction near the oil filter. They replaced the entire intake manifold and for the first time since I've owned this car it runs great, although as I drove away from the dealer it reset the CEL.

I pulled that and it came up as P0443 Evap Emission Control System Purge Valve C Fault. That turned out to be a fuel cap in which one of the mounting tabs has broken off. I have no idea how that happened, but that's what it was. The dealer was very helpful, and they did a great job! I just wanted to post my experience in case it could be helpful for anyone else down the road who might have similar codes come up.