98 540I Misfires @ 5k rpm

Ive been chasing this misfire for a while and its annoying already...

My car misfires around 5k when the the check engine is on... When I erase the codes the engine goes hard all the way to the redline... When the code comes back the misfire comes back...

The code im getting is for the ICV so I cleaned it and I still got the same situation, the ICV code comes back... How can I tell when the ICV needs replacing and is the ICV even the problem? I dont have idling problems which seem to be due to a bad ICV...

Ive also hollowed out the cats, changed the plugs and did the valve cover gaskets trying to rid my car of this poltergiest... I just want some feedback before I go and spend more $$$...

Thanks in advance for any help and advice!

Originally Posted by toofpik

Ive also hollowed out the cats

Wow. I was going to suggest the standard reference for misfires:
- How to diagnose a BMW E39 engine misfire (1)

But, if you've ripped out the internals to the catalytic converters, you're already far ahead of me on modifications to the vehicle.

I have no clue what I'm talking about but I would think removing the honeycomb inside the cats would have 'some' adverse effect on either vehicle operation - or - on smog results.

But I'll leave the answer to that nagging question to someone who knows what they're talking about (i.e., not me).
- How to remove & replace a catalytic converter (1) & how to fix rattling cat shields (1) & BMW P0420 codes related to cats (1) (2) (3) & cat autopsy photos (1) & what kills cats (1) & an EPA fact sheet on catalytic converter warranties (1)

As for the ICV, I typed /ICV F3 in the bestlinks to come up with these references for the OP' (but it looks like the OP may already be far ahead of where I can help):
- How to clean the idle control valve ICV in the E39 V8 (1) & I6 (1) (2) (3) (4) (5)

Thanks Bluebee but I dont think the missing cats r gonna cause any adverse effects (except for low end loss and a cel)... I know there was another guy with a problem exactly like mine and he posted his question in the newbie forum and his problem was ignored and never solved(or at least not on BF)... Im thinking my ICV needs to be replaced but i dont want to invest in more parts without being 100% what the cause is...

The thing that has me stumped is the fact that erasing the codes will cure the misfire but it always comes back when the check engine light comes back... Has anyone experienced this?