E39 - 540ia Vacuum Leak Cause Misfire?

[///Matt]

The GREAT people at "Autohaus of Clayton BMW" have my car in(97 540ia - M62)...again ghead They say that i've got a vacuum leak and that it is causing my engine to misfire (6 of 8 cyl's) is this a common problem? Is this even possible? Finally: would this cause my fuel pressure to be low....btw i did replace my gas cap a while ago...

[The Deuce]

A vacuum leak would cause a uniform problem across all cylenders, or at least on whole bank on a v8.

If you have two that appear fine, either you have problems there that will show when the vacuum is fixed, or it wasn't vacuum to start.

Low fuel pressure would be caused by something in the fuel system, not vauum. It either an electrical gremlin, or a mechanical failure. A vacuum leak may cause a lean condition, or a rough idle/acceleration, but shouldn't result in low fuel pressure.

[///Matt]

Ok, the car is back and fixed (i think)

Here is what Autohaus told me...(and billed me)

ALL MISFIRED BESIDES 4 AND 8
ADDITIVE MIXTURE ADAPTATION BANK 1 & 2 TOO LEAN.
REAR PLATE LEAKING AIR. SOME LEAKAGE AT FRONT PLATE AS WELL.
INTAKE PORTS ARE CAKED WITH CARBON BUILD-UP - EXTRA TIME TAKEN TO CLEAN.

R&R'D INTAKE GASKETS. PCV PLATE AND FRONT AND REAR COVERR GASKETS. CLEARED FAULTS AND RESET ADAPTATIONS.

PARTS COVER - 87.81
INTAKE MANIFOLD GASKETS 73.84
GASKET - 9.76

WITH 4.5 HOURS (@99/hr) OF LABOR AND $181.00 IN PARTS THE TOTAL COMES TO - 626.67


After that job I had to have my alarm system R&R'D for parts of $384.80 and $99 in labor...

bringing one day at the dealer to ..... ghead $1077.88

[PJV 528]

Thats the problem with the larger engines...maintenance costs are really expensive and one of the reasons i didn't got for a V engine!

In the UK, it would of cost double that!