95 840 CEL comes off and on and loss of power

[barry8108]

95 840, m60 engine. When cold CEL will stay on and car feels like it is down a cyl, runs rough and mpg is way down. They as car warms up it will flash on and off, each time it comes on power will drop. On warm days it is not as bad, light stays off most of the time. I have a BMP code reader and it is giving code 53, which says ASC intervention. But i read on Timms page that 53 is cyl 4 misfire? And if so would that be a bad coil? Thanks!

[Timm]

That certainly sounds like a single cylinder misfire - and as the cold weather affects it the prime cause is probably a vacuum leak around the manifold area. You would have better luck with INPA obviously - anyway, most likely causes are explained here:

http://www.meeknet.co.uk/e31/BMW_M60...cuum_Leaks.htm

.....or oil in the sparkplug wells:

http://www.meeknet.co.uk/E32/Plugs/Index.htm


...and as I said, INPA will give you a much better insight into the root cause of the problem:

http://www.meeknet.co.uk/e38/Diagnostics.htm


....Engine error code 53 (P0304) is Cylinder 4 misfire - and it is the rear cylinders that suffer most from oil in the sparkplug wells.....

[olinjohnston]

Actually I think this sounds like intake manifold gaskets...especially the one connecting the throttle body the intake manifold. Mine had a leak and did that same thing (only in cooler weather) until I replaced them.