W210 Misfire in Cylinders 5 & 2 at Idle

"Check Engine" light keeps on turning on. OBD reader indicates misfire in cylinder 5; misfire in cylinder 2; and random/multiple misfire errors. I have replaced all 6 spark plugs, the ignition coils, spark plug wire set, and added techron to gas to clean injectors. An inspection of the spark plugs show nothing unusual or different with plugs in cylinders #5 or #2. The same OBD codes indicating the misfire keep on re-occuring. The misfire only occurs at idle. Any advice for a DIYer without a service manual?

Reply to
DC
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What year 210 ?

Reply to
AJDalton7

1997 E320 151K miles, no perceived change in MPG, no misfire code when rpms are higher than idle.
Reply to
DC

OK That is the last year of 210 chassis w/104 engine.[later 210-E320 had v6 and below does not apply] The car has a waste spark distributorless ignition [ two plugs are fired from one coil ] Because both # 2 and # 5 plugs fire in series on 104 engines , the problem indicated is that you have a bad resistor connector under the front coil [ #2cyn]. You have changed the wires , but the wire set does not come with the plug connectors under each coil. Common fail part ... they are only $9 ea... I always change all three whenever changing plugs. Also . 104 engines run best on Bosch Super copper core , F8DC4 only... so be sure you do not have plats.....

Reply to
AJDalton7

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