Timing advance? Vacuum leak?

[dannywa]

My 1998 740iL "bogs down" when cruising at moderate speed and given a light load like a small hill. Not much at all when in sport mode. No problem when under hard acceleration. It's got 240k miles but runs great otherwise and has no codes.

I would think timing or a vacuum leak but the VANOS doesn't rattle and should be rock solid. I can't find anything that shows a vacuum problem and I have replaced most of the vacuum hoses.

Any thoughts?

[IcemanBHE]

Dont look too hard for VANOS problems as your car doesnt have it.

Id guess MAF or a cam sensor. Either could cause off running...and may or may not throw and error code when bad.

[zaherr]

My 1998 740iL "bogs down" when cruising at moderate speed and given a light load like a small hill. Not much at all when in sport mode. No problem when under hard acceleration. It's got 240k miles but runs great otherwise and has no codes.

I would think timing or a vacuum leak but the VANOS doesn't rattle and should be rock solid. I can't find anything that shows a vacuum problem and I have replaced most of the vacuum hoses.

Any thoughts?

It can be plugged catalytic converter

[Mayorchuck]

Welcome to the forum. Had similar issues a few years ago. Ended up being the CPS.