Audi A4 intermittantly throwing lean code

[Mark-in-CO]

My daughter just bought a very clean 2001 A4 Quattro 1.8T with 60k miles. Probably needs all the 60k maintenance stuff. Anyway, it has now started throwing a lean fire code. There is no noticable knocking and the code shows up a couple times per week; sometimes the SES light goes out on its own. Only premium fuel is used and I changed the oil promptly to Mobil 1 0W-40.

I am thinking of trying a fuel injector cleaner just in case this is the cause. Any suggestions?

 

[Quattro Pete]

A failing MAF (mass air flow) sensor could be another thing to check as a possible culprit. MAFs have a tendency of going bad on these VAG cars.

Also, replace spark plugs and air filter.

 

[moribundman]

If the vacuum tubing on this 6 year old Audi hasn't been already replaced at least once, I'd strongly suspect a vacuum leak. Even if this is not the cause of the lean codes, the vacuum tubing should be replaced every 3-5 years.

The MAF can be tested whether or not it operates within specs. I know how to do this on a 2.8, bit not on a 1.8T.

 

[Mark-in-CO]

Thank you for the ideas Quattro Pete and moribundman. It sure helps to be chasing the right fixes. With six different vehicles in our family to fix, I am a forever learning fleet mechanic for life...

 

[simple_gifts]

Perhaps for the time being you should change your handle to "Mark-in-NO"

 

[Auto-Union]

AudiWorld B5 Forum would be a good resource. Vacuum/intake leak is a good start. Maybe the airbox is not sealed?