Ian

Doug:

I too would side with Dave and suggest an intake leak. Check the system carefully. There are a number of ways of detecting intake leaks. Spraying carb cleaner (carefully) near various suspect locations is one. Propane gas, I am told, is another neater method.

I just did a top-end rebuild on my 1992 M5 and found a lot of the vacuum hoses a bit frayed at the ends. No leaks, but I was a bit surprised to see them so badly off. Also, TB gaskets and bellows (that get stretched when the engine rocks, specially if your motor mounts are done) are other things.

Neil Deshpande
http://www.neilwerke.com

***

Hi,
I've got an 88 M5 with 107,000 miles on it. I'm having a great time driving this wonderful machine but it seems to run rougher the longer I drive it. When it's cold it seems normal. Typical high idle on start up and quite smooth idling for the first ...say...half hour. Then I'm up on the interstate dicing with the best of them. When I get to the next traffic light it's running rough. Is this a simple as plugs and perhaps air cleaner...or is this truely temp related?