Have been gone for about a week.

Started the car up yesterday and it is running very, very rough. I have a code 21 on the HFM which Alldata says is
"ignition output 3 or ignition coil".

Just put new coils in about 6 months ago.

Any suggestions as to how to troubleshoot this will be appreciated.

Did you replace the boots?

Usually a misfire problem is caused not by bad coil wires but by the boots.

__________________
Paul S.

2001 E430, Bourdeaux Red, Oyster interior.
79,200 miles.

1973 280SE 4.5, 170,000 miles. 568 Signal Red, Black MB Tex. "The Red Baron".

Yes, I replaced the boots when I replced the coils.

Thanks.