Paul:

Yeah, but! Late valve timing (it's VERY unlikely to go fast, eh?) would give late power -- usually the effect is low power at lower rpms -- the power is still there, but you have to spin faster to get it, until you get to the point that compression goes down because the intake is open part way up the compression stroke. Usually bends valves on a Benz if its THAT late. Easy enough to check, too -- if the chain is stretched enough to make the engine run badly, the quickie line up the notch system will tell you pronto.

Late valve timing won't make it go rich, though -- this is metered FI, it will only add proper fuel for airflow unless the fuel distributor is buggered. I'm no expert on ignition traces, but all the ones I've seen have a fairly straight line for zero voltage, not the jagged bouncy stuff I see here. Could easily be overrich, but why is combustion going to pot at high rpm? Given that fuel flow is determined by airflow, I still think there is a misfire problem first.

This is presuming that there isn't anything else wrong, though, like a hole in the cat or something. Or toasted or disconnected O2 sensor.....

He doesn't say if it runs better with the EHA unplugged -- this would tell me more.

One last note -- if the coil (or wiring) is bad, would it do this? I had a bad coil on my old Dodge Aires that gave similar results -- lost power under load. New coil fixed it.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!