[mustang67408]

Originally Posted by SyKoHPaTh

Hey there! Signed up because of the valuable information here.

I'm currently receiving the P0172 code (fuel too rich) from my '00 Echo.

The symptoms I have are exactly what I've read at the beginning of this thread - idle speed is lower than normal, car stutters on acceleration.

I cleaned the MAF sensor (it was FILTHY, like, entirely black on one side!) - I noticed immediate improvement, but the same code popped up again 2 days later. I cleaned the sensor again, thinking I may have missed a spot, but the light reappears shortly after. I cleaned with the non-chlorinated carb/brake cleaner, and dried off.

A couple things that may or may not be important: I used to drive this car over long distances (1 continuous hour twice a day, freeway driving) - I used 89 fuel because I actually got much better gas milage than the 87 I typically use. At the start of this year, I moved closer to work, and my drive time has been cut down to 4-10 minutes, city driving. I stuck with the 89 fuel out of habit - could that be the culprit for "fuel too rich"? The check engine light started appearing about 9 months after I moved.

Any help is appreciated, thanks!

"FUEL TO RICH" P0172 means the engine is running to lean and the computer is dumping more fuel thsn it thinks it should be for too long a time. I would look for a vacuum leak, vacuum hoses on wrong, a leaking brake booster or a plain old BAD MAF.
Need scan tool data and some on hands to figure out which, but this should get you started.