[W126 Coupe] Hesitation from 60C to 80C

[Day . Ralph]

The same thing happens to my 91 and did to my 84.  My mechanic (a certified MB mechanic) could not figure it out.  Yup, happens only when it is cold.  I noticed that Marcus sent a single word "vacuum" but where?

Ralph D. Day
Senior Program Manager/ASQ LSS Certified Black Belt
MDA Master Black Belt
Dynamics Research Corporation
(301) 275-9030 (cell)

From: mbcoupes-bounces at mbcoupes.com [mailto:mbcoupes-bounces at mbcoupes.com] On Behalf Of Matt Jurcich
Sent: Sunday, February 08, 2009 12:41 PM
To: mbcoupes at mbcoupes.com
Subject: [W126 Coupe] Hesitation from 60C to 80C

Hey all,

My 89 560 SEC (110k or so) runs and shifts fine from cold until about 60C.  It starts to hesitate, tranny shifts way late (it's scary if you're on the freeway and can't keep speed!) but then when the temp gets up to 80C (running temp) the power comes back and shifting is normal.  Car is completely fine until it cools off.

I changed the fuel pressure regulator, had my fuel filters changed at the pumps about a year ago, tranny service a couple of years ago, changed plugs, rotor and dist cap last year.

Any suggestions?  It seems like some temperature sensor that's flaking out......

Thanks.

-m
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://www.pairlist.net/pipermail/mbcoupes/attachments/20090208/35279c30/attachment.html>