Yikes, engine missing...
 

OK, not missing as in suddenly not in the car, but the motor is definitely hesitating/missing right at 4200 RPM when accelerating.
I have been chasing MFI gremlins (backfire when lifting throttle at 3000RPM) and wonder if they are related. Ideas?
Thanks, and Merry Christmas

Check:

plug-gap, plug-wires, worn rotor/cap, micture too lean?

missing
 

Glad you clarified that missing thing.
Check the points for correct gap and then check the timing. I have found that at times I jave had to hold my foot down and the plugs cleared up and strted firing as they should. And they were relatively new plugs too. It is easy to foul a plug after chasing gremlins and running the engine at low RPM and no load.

that would make sense, there has been quite a bit of idling in lotws of holiday traffic lately, several hours worth. Noticed the hesitation/miss when I finally pulled into our neighborhood and I went to open her a bit. Will pull and clean the plugs tomorrow after the onslought of Christmas passes..
Thanks and Merry Christmas
(oh, and if I didnt clarify teh miss thing, somebody would have asked me to check behind the rear seat... )

missing
 

And you would have found Christamas presents!!
Happy Hollidays

After all the basic tests as mentioned above, check the coralation of the throttle rods. Check the speed relay for proper setting and if it is functioningm as well. Checks for air leaks. That is done by spraying STARTING FLUID at the injection stacks and see if the motor changes speed. But the most important too; you need is a CO machine. If you have anymore questions, call me and I will explain it to you on the phone, because it would take me two days to answer you via my slow typing. OTTO(71 911E mit MFI)