Rough running engine

[jpressick]

Some months ago my 250SL engine was rebuilt.  Since then the engine  misses after start at idle and while driving especially in 3rd and 4th gears.  In the process of eliminating possible causes the air filter, the fuel filter, the fuel pump have been replaced along with cleaned and checked out injector nozzles.   A 123 distributor was also added.   The injector pump was rebuilt by Hans a couple of years ago.  The car starts up immediately.  The plugs all appear to be firing. One of the questions I have beside the obvious is the wiring going to the starter solenoid and the fuel cutoff solenoid on the rear of the injection pump. There are two wires, one is red/green and the other is pink/black. Which one goes to what solenoid?  Now the important question.  Anyone have any suggestions on what I can try next to get my beauty running smoothly again?  Thanks Jim  1967 4 speed

[Bob Killam]

My 250 had A slight skip occasionly and electronic ignition conversion cured it.Im sure You will find your problem on this site shortly,Hope this helps,
                                                                     Bob K

[Cees Klumper]

if you have not already done so, try a fresh set of spark plugs, I've more than once been amazed at how even relatively new plugs can go bad (just this week on my riding lawn mower as a matter of fact). And check the resistance of the leads.
Your wiring question should be addressed in the color-wiring diagram here on the site (thank you Achim once again).

[Naj ✝︎]

Since its a newly rebuilt engine, I would start with retorqueing the head and checking valve clearances.
The follow suggestions given.

naj