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Lawrence Coppari Lawrence Coppari is offline
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Join Date: Feb 2000
Location: Kingsport, TN
Posts: 2,925
A vacuum leak would affect the boost. If the boost remains where it is supposed to be, I don't think a vacuum leak is your problem. Besides, a vacuum leak has little effect at full throttle other than screwing up the boost control. So much air is going into the engine, a small leak is dwarfed. Aside from boost control, a vacuum leak manifests itself at idle, not full throttle.

First thing I'd do is replace the fuel filter or at least remove it and try blowing through it in the direction of fuel passage. There should be little resistance. Don't smash your knuckles getting it off. Don't get fuel in your ear, etc.....

Next, I'd take a good look at the spark plugs and wires. Remove all plugs and compare them. The cylinder that is misfiring probably will have a different colored electrode tip.

What about a malfunctioning fuel injector? How are your distributor/rotor?
1986 951
2002 SLK32 AMG
1987 328GTS
2011 528i
Old 07-14-2004, 04:43 AM
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