Man, I feel for you. I have had a warm start problem on my '91 300 for 12 years, and no really good solution yet. It misses like crazy for 5 seconds, then smooths out, so it's an opposite problem than yours I suppose.
If you indeed have actual cylinders mis-firing at idle, a good shop should be able to attach a scope to the ingition system, and isolate the exact cylinders that are missing. this should provide some good data to work towards narrowing the problem.
Have you checked the EHA for proper function?
I know you said you had the idle mix checked several times, but maybe you should go ahead and buy a $30 Sears multi-meter with the % dwell and the mAmp capability. Then you can check the % enrichment of the EHA, and also the actual mAmp current through the EHA at various rpm and temp conditions (you have to build a simple wire harness, no big deal).
There are several articles in the Forum here about how the EHA works, and affects the mixture and air valve settings.

Oh, to bridge the fuel pump, pull the MAS unit out (do '86 models have a MAS like the "91 models?) and bridge terminals 1&2 on the socket.

DG

the pump relay is under the windshield on the right side. forget what it says but it is not the one that says klima. jump 5&7.

george

I having the same problem as you....


I have a misfire that appears just after startup.... I have replaced just about all of the same stuff as you, high compression across all cylinders, both Beru and Bosch silicone wires, no difference, new rotor, cap, coil, fuel pumps, fuel pump relay, OVP, filter, fuel distrubutor, you name it, its been replaced.....




I am still hunting down that damn misfire, and this coming weekend, I am going to try and replace the injector to see if it fixes it.. Then I am going to swap out my EZL to see if that works.


What cylinder do you have the misfire on?

__________________
-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

Does it sound like the same thing by my description on the first page?

Also I honestly don't know the difference between a "rough idle" and a misfire? What's the difference?

There is no specific cylinder...its just random sputtering. I just managed to find a working Fuel Distributor + EHA valve for $70 shipped...so I will give them both a try and if they make no difference...I have 1) spares now or 2) sell them for the same money or a little more. I am keeping this car until it dies so money spent now isn't going to waste as if the thing in 75,000 miles needs a new fuel distributor, there it is in my 300TE box of parts

Oh and Justin, away from the misfire issue, does your 300TE go to the redline in 1st gear? (not 2nd, the real 1st) In 1st gear the car shifts at ~4000rpm into 2nd and then goes to the redline before shifting to 3rd....I don't quite understand why it shifts too early in 1st. It will happily go to the redline in 2nd and 3rd...but doesnt want to do it in 1st even with the kickdown switch pressed. Just making sure this isn't normal.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

Mine pulls hard all the way to redline.....



You can drive it....

Its more of a rough running idle thing.... I classify idle as everything below 1200 RPM.... When it hits 1200, it feels really smooth, like nothing is wrong, and it pisses me off hella bad.


It sound identical to what you have going on....

__________________
-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

Hmm...so my gear slipping before reaching the redline in 1st isn't normal (didn't think it was)...but it is probably unrelated to my misfire.

I am definitely going to take my wagon to Enrique in San Fernando Valley and get him to try and figure out the problem. I called him up and he just said bring it in on friday and he'll take a look.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

The car seems to be getting worse day by day now. It stalled right after putting gas into the car yesterday. I filled up, started her up, moved about 3 feet and she just died. Took her 10 seconds of turning to get her to start back up...

Sigh...it never ends with this car. Taking her to Enrique on friday so maybe I can have some damn luck for once.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

I put 76 in my car, and dear god, it ran the worst its ever been.



Put chevron back in, and the misfire is a little better.



Try pulling the R16 resistor for the timing... I did it, and it idles a little better, but still idles poorly.

__________________
-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

Yeh I have mine out permanently now (have it in the car just in case). I run 89 for my car. I have tried both Costco and Chevron and I feel no difference.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k

Ok guys I'm back!
Been really busy with finals at school and was waiting for my dad to help me put in this fuel distributor.

We put it in successfully, but problem is not solved

At first it was starting really horrible. Idling at 500 caused it to really shudder....but then we adjusted the fuel mixture and it feels about the same now.
Now, just to keep you up to date, this was a used fuel distributor, but the likelihood that I obtained one that feels exactly the same must be pretty small...There's no difference at all.
Oh and forgot to mention, this actually solved my premature shifting in 1st gear! YES! Wasn't expecting that to happen, but it seems to be going all the way to the redline now instead of shifting prematurely at 3-4k rpm

So back to the game plan now then. Next would be the Fuel Pressure Regulator correct?

Oh another question I need to ask: When the multimeter is connected using the ground wire, is the % it reads rich or lean? When it shows 45%, is that 45% rich or 45% lean?

Thanks guys!

Justin: Did you get around to doing the injectors? Just curious, have you replaced your FPR yet? This seems to be missing from both of our fix lists.

__________________
2016 Monsoon Gray Audi Allroad - 21k
2008 Black Mercedes E350 4Matic Sport - 131k
2014 Jeep Wranger Unlimited Sahara - 62k
2003 Gray Mercedes ML350 - 122k