Hi!

I have a MB 420SE from 1990, with the 116.965 engine.

Short question first: If my injectors are leaky, wouldn't this cause rough starts both when the engine is hot AND cold, not only when hot?

I have a few symptoms:

1. Acceleration is sometimes jerky when the engine is cold. It's like the engine just loses power a few split seconds here and there. As soon as the engine is warmed up (after five minutes), the problem goes away, although I sometimes do notice slight stumbles at idle.

2. Hot starts are usually rough. It fires rather quickly, but doesn't fire on all cylinders until 2-8 seconds have passed.

3. Valve tick and general valve chatter when the engine is hot. Not very loud, but hearable if you know what to listen for, especially the tick. The sound isn't constant, and phases in and out a little.

Background:
a. If I accidentally turn off the starter motor too quickly when the engine is hot, just so the engine doesn't fire completely, it is impossible to start again the next couple of minutes. It cranks, but there is no sign of the cylinders firing. If I leave it alone a minute or two, it fires up to the "normal" rough hot engine start. These rough hot starts have been there since I bought the car a year ago, but the jerky acceleration when cold only started happening a few days ago.
b. There is a small gas leak around the EHA valve, I will try to change the seals.
c. Fuel consumption is normal, at 1,28l/10km with mixed driving.
d. The engine is otherwise very responsive and running fine.
e. The engine uses around 0,6qt per 1000 miles (0,4l per 1000km). No blue smoke, exhaust seems to smell normal.
f. There is a slight oil leak/creep around the breather hoses, both at the valve covers and at the IAC. The hoses are almost rock hard, and I will buy new ones.
g. There is a smell of gas and oil up in the air filter, but it doesn't seem excessive. There is a little oil in the breather hose between the passenger side valve cover and the air filter.
h. I quite often have a high idle, at around 950rpm.
i. Have tried to spray start gas around the injectors and manifolds, couldn't find any vacuum leaks.

Parts recently changed:
- Rotor, distributor, spark plugs, spark plug wires and ignition coil wire is new.
- New chains rolled in a few years ago, along with new cams, rocker arms, valve steam seals, two upper guides and oil rail clips.
- All new drive belts.
- New thermostat.

My thoughts:
Regarding the rought hot starts, I was suspecting that the fuel injectors wasn't holding pressure, and was leaking fuel into the cylinders, but since it isn't a problem if I start, stop and start a cold engine, I wouldn't think this is the issue. The fuel quality in Norway is very good, and I'm running on Shell V-Power 98, which is the most expensive high octane fuel there is in Norway.

What do you think can cause my symptoms?

Picture of the EHA-leak
Picture of the PCV/rubber-hose leak

Picture of my Benz, if anyone's interested:

If it were mine, I would replace the two O-rings in the EHA, and give the Idle control valve a really good cleaning (visible in your 2nd picture - has part # showing on it...I looked it up, they are not cheap).

Good luck!

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09 Jetta TDI
1985 300D