Hi, I was curious if anyone has this same problem with there Merc. I have a '90 300SEL with 75,000 Mi on it. When I burn Sunoco 94 octane all is well. As soon as I fall below that 94 I get a "stumble" at start up. This is brief but noticable. If I step on the fuel pedal while starting it is less of a problem. It almost acts like it is losing fuel prime but not sure that could be it. I was thinking new injectors but someone said they either work or don't. I have a new fuel filter and new wires and plugs about 4-5 years ago but not many miles on them. Anyone have any suggestions? I could put a new set of plugs in it, maybe Platinums and see if it helps. I believe something else is doing this. Look forward to any replys.

Hard to believe not one reply to this post. Thanks for the help.

I think you answered your own question - use good grade fuel.

Mike.

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1990 Euro 190e 2.0l Petrol Now Sold Maybe a w116 280se next

I would try the double-dose of Techron approach first. Add two bottles of Techron fuel injector cleaner (not fuel system cleaner) into less than a full tank of fuel. Go drive the car hard when warmed up and see if you can get the mix to clean your injectors.

Your engine specs a 91 octane, so if the fuel is good that should be enough.

I do this will all the cars periodically and it definetly helps.

I change the oil afterwards.

Haasman

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'95 E320 Wagon-Went to Ex
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'65 911 Coupe (#302580)