i have a 1980 merc 280se, or 126D europian manufactured.
when i push on the gas the rpm will go up slightly then the engine bogs down
and the rpm drop below 400. the vehical starts, and idles ok, it's just when I
push on the gas. and if I put in gear it will run... but only at about 5 mph. does anyone have any ideas?

I'd really appreciate any help/advice any of you can give me with this problem. This car is my daily driver, and it's been a real inconvenience having it out of commission like this. Please let me know if you need further info to help with a diagnosis. Thanks in advance!

what engine is it?

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1987 300e manual 250,000 km (sold)

It's an in-line 6.

Well, that's a start. That means its probably an M110 engine, check your VIN and see. The engine number will start with either 110.987 or 110.989

Don't know what the difference is but I do know there are a number of fuel injection systems used with that engine, find out which one you have and do a search. Plenty of information in this forum if you can be a bit more specific.

good luck

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1987 300e manual 250,000 km (sold)

Sorry for the delay in getting this info:

The number on the driver's side engine block is 1100111101.

The car has been timed/tuned properly, has new rotor, dist. cap, plugs & wires, new fuel pump & filter, and a new air filter.

Again, any help with diagnosing this problem will be GREATLY appreciated!

(intake manifold vacuum)... and what is it doing while the engine sputters?

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-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

it stays just a little bit before the halfway mark, but will go as far as the halfway mark as the needle shakes a little.

I was thinking vacuum leak but that doesn't ring any bells in my limited personal experience.

Have you considered getting the fuel pressure tested?

__________________
-Marty

1986 300E 220,000 miles+ transmission impossible
(Now waiting under a bridge in order to become one)

Reading your M103 duty cycle:
http://www.peachparts.com/shopforum/831799-post13.html
http://www.peachparts.com/shopforum/831807-post14.html

does that model have a fuel accumulator like the 450s?
they're known to go bad an impact fuel pressure.

on my recent purchase of a 76 450sl, it ran terrible (and barely)
when I got it. fuel system was all gunked up from neglect, etc.

a few bottles of Techron in the fuel system really did wonders.
I still have work to do but cleaning up the delivery system helped
a lot, and was easy.

sounds like bad mixture to me, which culd be for a number of reasons, gunk in the system being just one.

what sort of fuel injection system is it?

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1987 300e manual 250,000 km (sold)