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1998 BMW 540i Repair Question


Topics covered: Engine, Intake manifold, Rpm.
Mileage: No information provided.

Asked on December 29, 2009

1998 BMW 540i bank 2 misfiring

Engine Performance problem
1998 BMW 540i V8 Two Wheel Drive Automatic 84000 miles

I replaced my valve cover gaskets this past summer because of oil leaking into the plug wells. I recently replaced all 8 spark plugs as well. Using the Peake code reader, the codes I am getting are "misfire detected, cyl. 5" & cyl 6, 7 & 8. Additionally, there is a "random or unknown cylinder" misfire along with "catalyst damaging" on cyl 5, 6, 7 & 8. I've swapped the ignition coils & the misfires are still on cyl 5 - 8. Also, the pre-cat O2 sensors were replaced about a year ago.

The check engine light flashes during wide open throttle beyond 3000 rpm & it struggles to rev past 4000 rpm - I took my foot off the accelerator after a while, thinking that I might do more damage if I tried to push it beyond 4000 rpms.

Thanks in advance.
Avatar Asked by goose1207

Answer

Replied on December 30, 2009

A flashing check engine light is not good. It indicates cat damage is occuring. Tell me all that has been done to the car, I need to know if the intake manifold has been off and if the PCV plate is original.

Tiny Answered by Dr. Hagerty (expert)
9,669 answers provided
Replied on January 2, 2010

The intake manifold hasn't been off & the PCV plate is original. I'm assuming that the PCV is the same thing as the CCV? Do I need to replace the vacuum lines & rear intake manifold gaskets? How much time is required for a weekend mechanic to do this?

Thank you.

Tiny Response from goose1207
1 question asked
Replied on January 2, 2010

The job can sell for 5 or 6 hours and what will need to be replaced is not clear from cyberspace, but it might mean everything.

Tiny Answered by Dr. Hagerty (expert)
9,669 answers provided