[W126 Coupe] Hesitation while driving

[Chet Hwilka]

The fuel pump(s) will change pitch slightly as the load changes.  So I would
not use that as a guide to replacing it.  You need to check the fuel
pressure to be sure..
And as far as the hesitation, there are is ton a causes that have to be
diagnosed.  If you're going to get deeply involved in diagnosing your
problem this book may help.
http://www.amazon.com/Bosch-Fuel-Injection-Engine-Management/dp/0837603005/r
ef=sr_1_1?ie=UTF8&s=books&qid=1272806353&sr=1-1

But hesitation causes can be; vacuum leak, clogged injectors, leaking cold
start valve, dirty/sticky fuel dist plunger, airflow plate to mention a few
of the obvious. And these are just the F/I cause.  Could also be ignition,
electrical or even internal engine.

Sorry if I stated something already covered. I haven't been following this
thread.

Chet


-----Original Message-----
From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com]
On Behalf Of Sean
Sent: Sunday, May 02, 2010 8:37 AM
To: dan at landiss.com; Mercedes Coupes Mailing Lists
Cc: mbcoupes at mbcoupes.com
Subject: Re: [W126 Coupe] Hesitation while driving

..... Ordered new pump. Waiting. Did I waste my money??....