26 and 27 multiple fuel trim 1 and 2 limit reached

[Nelson Stacks]

Hello all, I have a 2001 with 45k miles, yes I know, I do drive it, and I love the car.
I have had intermittent CEL coming on for about a year or so, each time I reset the code by unplugging the battery and it takes about 5 months to come back on.
The engine does NOT idle rough, it runs perfectly. I went to a shop today because even after battery reset the light was coming on after a few hours of driving so I figured the problem was getting a lot more severe.
He used a snap-on reader and saw 27 multiple fuel trim 2 limit reached and 26 multiple fuel trim 1 limit reached. All other readings were perfect from his reader.
He said I should get a tune up and it may cure it, spark plugs, perhaps coils, etc..
I don't want to blindly change things, especially the MAF which I believe would cause the car to idle very rough if it was bad, and the car idles perfectly and drives beautifully. He reset the code but it came back after 2 minutes of driving.
I have read so many postings and people have many opinions of what to change, ranging from plugs to gaskets to MAF and MAF sensors.
Any thoughts other than a massive overhaul and blind changing of things from this small independent shop here in Massachusetts?

Very much appreciated!
Nelson

[Nelson Stacks]

It's a 740i, sorry to have not included that before.

[BMWFXR]

get it diagnosed properly. This could be items that include spark plugs, air filter, fuel filter etc but more than likely you have a vacumme leak. This is best found with a smoke test....smoke is forced into the motor via the intake boot at low pressure which comes out where there are vacumme leaks. Additionally you could have a bad MAS but that is a lot of money on a guess. If you don't have a shop and need one, try www.bimrs.org for a reputable BMW specializing indy. Trent Cole, Tech Advisor, Lone Star Chapter, BMW CCA
President, Lone Star Bavarian, Inc.
FT. Worth Tx, 76132
www.lonestarbavarian.com

[claudio512]

If you were in Dallas, Texas... Trent Cole would be your solution. However, as he has explained some of the possible problems without adding other engine sensors... I hope you find someone as good as those guys at Lone Star Bavarian in Dallas...



"Keep Right, Pass Left. It's the Law."

[Nelson Stacks]

Thanks for that T Cole, that is indeed what I'll do. I will check on the link you provided to see who is good in the boston area! Thanks very much for the reply, very much appreciated!!!