Annoying SES light, search function didn't find my problem

[preppy]

So I have the dreaded SES light on my 01 4.4i. I've had it come and go for the past 6-7 months. It's only happened after I moved from Maryland to Denver, CO last August. Before being in CO, the x5 has been in TX and MD from 01-07.

So I take the x5 to a good indy shop to have the code read and to repair whatever the problem is (crossed my fingers it was a bum gas cap). Well, they read it and it tells them the car is running rich...okay...well, then they reset the SES to figure out what specifically is causing the car to run rich. Nothing odd, mechanically/eletrically shows up and the SES light doesn't come back on.

They run a battery of tests on her and still nothing, the only thing off on it is that the alternator at one point put out a really low voltage, but then corrected itself.

So we decided to give the x5 the weekend to see if the SES light comes back on. I was getting slightly poor gas mileage before I took it in (10-12 by rough guestimation), but after resetting that, the x5 actually gets about 13-15, which is about right for driving around town in traffic.

So what could be wrong with my x5? Should I just have them order me a new gas cap regardless?

[Big "J"]

Assuming you run 93 octane..have you done any injector cleaning?

[preppy]

You know what....I went down from 93 on the east coast to 91 out here in CO. Do you think my injectors could be dirtier from the change in octane?

[Big "J"]

Could be.... 10% ethanol doesn't help in any grade. Plus, stations don't monitor the amount of sediment that collects in the bottom of their tanks that can gunk up filters and injectors.

I have a 2003 3.0 and for good measure I perform the "seafoam" injector cleaning about every 6,000 miles because of the potantial for build up. You can get it at O'reilly's or Autozone. I change the fuel filter about every 10K.

[vinuneuro]

Running rich is usually Oxygen or Mass Airflow sensor related.

[lo_jack]

Originally Posted by vinuneuro

Running rich is usually Oxygen or Mass Airflow sensor related.

Exactly. This is either an air or fuel problem, or a sensor problem...outside chance it is neither and something is actively leaning you out and the ECU is trying to compensate, like for instance a seperator failure.

[binhly101]

are you filling up with top tier gas? I drove around for months with the ses light on, no one knew what was wrong, then one day my indy asked me where I was filling up and the moment I changed over to strictly top tier the light went away and never came back.

[preppy]

It's been awhile since I checked my air filter, I wonder if that might be effecting anything?

God, I wish my car would just tell me wtf is wrong with her rather than me having to check (and recheck) and speculate about things...

[Big "J"]

Yeah..... if our cars could tell us what's wrong and pinpoint the issue then we wouldn't need the automakers and stealers fixing them for us and charging outrageous prices.

[mysweetx5]

Originally Posted by Big "J"

Yeah..... if our cars could tell us what's wrong and pinpoint the issue then we wouldn't need the automakers and stealers fixing them for us and charging outrageous prices.

Yea guys! I just wanted to add something more... Many people think is all about BMW vehicles! But it's not, because it doesn't matter whatever car models you have; any mechanic shop specially the (stealer) would tear your bank account up.
If you don't mind to spend all your pocket out to mechanic shop, the most important economic way to own any car is: (Knowing a few basics stuff about engine mechanic) . I have my cousin in MD who owned a (2005 Nissan sentra SE 4cyl)
very small size little car. And she wen't to a mechanic shop to change her front Brake pads only, and the shop required: $375+ just to replace the front brake. Is it reasonable guys to not knowing how to do certain basics stuff in our vehicles??? Imagine how easy it is to replace brake pads.