1993 Other Mercedes Benz Models engine speed goes up & d

1993 MERCEDES BENZ
168,000 MILES • 6 CYL • 2WD • AUTOMATIC
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1JACKZOOMER
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Hi, my grandaughter has a M-B 300E engine performance problem, when fiirst started hot or cold the engine speeds up & down but seems to run ok on the highway. any help will be appreciated.
Jan 4, 2008 at 8:52 PM
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2CARPRO JACK
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Are you saying that is surges at idle? When was trh elast tune up? Might also want to check for any vacuum leaks, they will cause an idle fluctuation
Jan 5, 2008 at 8:15 AM
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1JACKZOOMER
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it had a tuneup last summer, after i changed the oil & filter today it would only start by pumping the gas pedal 4-5 times & the idle speed is getting worse ,up & down 4mto 500 rpm. yes i have looked for a vac. leak. wondering about the fuel pump or the cat. converter? thanks again
Jan 5, 2008 at 6:55 PM
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2CARPRO JACK
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Need a manual gauge to check fuel pressure, you can try loosening the exhaust before the cats and run it, loud but if the cats are the problem it will run ok.
Jan 6, 2008 at 7:33 AM