[W126 Coupe] 560 SEC hiccups

[Dick Spellman]

Hi Jay,

Check the o2 sensor whcih could be pulling the air/fuel lean at idle.  You
describe good running at speeds but the stumble when you come to a stop.
So, the basics will be check the lambda and o2.  (I'd say O2 first.  Next
would be check the coil to cap lead at night for arcing.  Use a spray bottle
with water across all leads for a similar condition. Do not disturb any of
the leads as this can worsen an aging lead.

A helpful question or two, if you have the details would be: How many miles
on (electrics)  the O2, leads, plugs, rotor, cap?

Regards,
Dick



On Tue, Aug 31, 2010 at 1:39 AM, Jay Hirsch <j.hirsch at mac.com> wrote:


> I know this was discussed  recently

>

> Yesterday went  on a 280 mile trip, 75 mph with my 1990 560SEC.  Also got

> 19 mpg

>

> Got gas  twenty minutes from my home, where I usually get gas for all my

> cars.

> Five minutes after getting gas car started to have a  "hiccup" or slight

> miss while stopped for traffic  light.

>

> Light  changed, give  the car  gas and runs fine.  Come to stop and  car

> idles  a little rough,  slight miss.  almost seems to want to conk out.

>

> Will point until I got gas car was cruisin between 70-80 mph,  all highway

> driving

>

> Same thing today, once  the car warmed up car idles rough with slight

>  surge up and down,

> Give the car gas, pedal to metal and runs OK

>

> What sensors, vacuum line or relay should  I be looking at?

> thank you

> keep cruisin

> Jay H

>

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