1999 528iAT mileage

[dmaisenh]

I currently have a 1999 528i Touring Automatic and am getting about 16 and a half MPG in city driving. I used to have a 2000 528i sedan manual and got 24 MPG in the city and 32 on the highway.

I know the wagon is about 300 lbs heavier, has the roof rails and a different rear gear. But my question is, is my mileage what it should be for should it be closer to what I got with the 2000?

It has new plugs, good air filter, and I just cleaned the MAF. I was going to pull the IAC and clean it but was having to put so much force on it to get it out of the grommet that I was afraid I would break something.
The idle doesn't seem a smooth as it should be. I was thinking about replacing the CCV but have no real indications of failure.
The car does run great but I just feel that the mileage should be better.

[WBAD530i]

Not too surprising for an automatic if you're driving strictly in the city. Spray some lube around the grommet and twist it. Check the throttle body gasket too. Intake gaskets? CCV preventative replacement isn't out of the question either. Is it cold where you're puttering around? Short drives in the cold will build up and could make the ccv fail sooner than expected.

[geargrinder]

Yeah I think that's pretty low to attribute to just 'slushbox'. Is that real measured mileage using gas-fillups, or OBC? Are tires the right size? (aka not a mileage measuring issue?)

[edjack]

What are fuel trim numbers?

[mattmar1]

was just fixing to ask the same as edjack....and also have you checked for vac leaks lately? that was the cause of a mileage issue i noticed last fall on my 528i manual.

[dmaisenh]

I have NCS and INPA but I have not seen where to read the fuel trim.

[Mike WW]

Has the Vanos been done? I had a 00 528ita that got 25-26 in a soft commute plus other driving. But when the Vanos went south it was down to about 19. M52tu's seem especially affected by Vanos failures, while it ran fine, except for surging and occasional stalling on cold starts, the car was definitely down on torque so seemed kind of doggy.