1973 450SL. Rough running HELP!!!!!

[Tomadaly]

Where to start... Need help as nearing the end of my patience.... I have a 1973 450SL . European car .. Good but not great. 5 years without any big difficulties but has let me down 3 times in last 5 months .. New fule pump and new coil were the first 2. *Couple of weeks ago it started to run really rough. *When driving it was ok but when coasting and then accelerating it chugged a couple of times before taking off ... Then started to run rought in traffic *finally had to abandon it at a garage ... They said they were familiar with 107's so seemed like a good idea.

They bypassed the electronic ignition .. New coil and points and said this should solve the problem.. They also did a pressure test on fuel and said pressure was not holding for long enough when the engine off and suspected an injector leak.*

Took it home 50 miles .. Now back running rough.. Even on tick over

Have tried the following..
Fuel addetive to see if it will clear injectors but no more than 10 miles since added
Checked all connections to ECU based on 07.4-035 from manual
vacuum hoses and connection seem fine
Trottle switch clicks OK
Temp sensors are within spec
Injection valves resistance is OK

I plan to check trigger points and timing using a timing light but this is outside my comfort zone

Question ?... Beside the air valve there are 2 connections .. One is the temp sensor coolant connected to ECU.. The other has a rectangular dark brown connector .. 2 brown wires .. Engine dies when disconnected ? Whats this for .. Reads 32 ohm when engine cold...

I really shoud take it back to the garage but I dont think it will struggle that far.*
Any suggestions on where to go from here. *

Sent from my iPad

[meltedpanda]

if they put in new points I would hope they timed it, did you ask? how many miles and are the trigger points original?
did you check the cold start valve?
Plugs /plug wires?
how does it start cold/hot ?
a little more information and perhaps we can help

[Tomadaly]

Thanks for fedback.

They put in new coil, condensor and points .. They tell me timed correctly.

No idea about trigger points .. I expect they are original .. 136k miles

Dont think it has a start valve issue .. Starts fine .. Sometimes runs rough .. But mostly when driving hesitates when i try to accelerate or whne i take foot of the accelerator and back on again .. Like its missing a few cylinders when trying to pick up..

Im thinking of a pertronix conversion and having the injectors cleaned..

[meltedpanda]

At 136 K I would suspect injectors and TP as culprits, especially if she starts OK warm and cold. Petronix is a good idea , I did that to mine. You could also have a "out of sorts" TPS which might need cleaned. Search my name in SL forum and you will find all you need to know about you tuning your car