I've just recently purchased a '94 E-420, 1-owner Benz. Thoroughly enjoying the vehicle. It has 110.000 miles on it and while idling in my driveway about 2-3 weeks ago, it began to sputter and simultaneously the Check Engine light illuminated. The idle problem is intermittant and without any apparent pattern. When the motor begins to sputter, the idle RPM drops to 250. The light doesn't flash, nor has it ever since this problem began. Vehicle just passed emissions two weeks ago, and very well I might add. This suggests to me that the oxygen sensor(s) are probably not the problem.</P>


Any ideas? I don't have any diagnostic software, PDAor info manual and since I'vebarely owned the car for a month, have'nt selected a qualified service center either.</P>


I've wondered if it's the change in altitude. Could this be or does anyone have any other ideas?</P>


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Please advise.</P>


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mgl8121</P>

 

Before going too far into changing parts have your wiring harness checked. The '94-95 models are notorious for having defective wiring harnesseses. I have been there. Best bet is to have someone plug your car to an analyzer and check how many faults are reported by the system. If you have more than one, I bet it will be the harness. You can also check the harness wires and see it the insulation disintegrates when you touch it. The cost of the harness is+/- $750. If you have someone change it, labor will be +/-$400.

 

Thanks for the info. I'll do that.