Hi everyone!

Had my X's for a few years now and have always read and read this forum for valuable information anytime I had an issue or needed a fix. I can't seem to nail down what is causing the CEL after a hard acceleration.

Firstly, its 2009 4.8i. Few weeks ago I had the CVV changed due to heavy oil consumption. Fixed that issue so far.

Drove a week or so and everything was fine but after passing a car on the highway, the CEL lights up. Had my INDY (buddy) scan the computer and I get P2178 " System Too rich off idle ".

He reset the computer thinking that perhaps the system was compensating for a clogged CVV and now all the parameters needed to be reset. Cleared fault code and drove around for another week or so. Again, hard acceleration merging onto highway throws the same code. No code with regular city driving only when I give it some extra power.

I do experience a slightly low RPM at idle which I can feel in the form of a slight vibration in the steering wheel. Not a big deal and maybe its in my head.

Bought the truck off a relative in 2013 and have been relatively problem free since then.


Changed spark plugs a year ago
Used Techron cleaner last week

Based on what I've read in this forum, I will be looking into:

MAF
O2 sensors
low pressure fuel sensor
fuel filter


Any thoughts?