This issue is strange to me, and is on a 97' E300D OM606. The car runs decent until it crosses the 40'C mark then it starts to miss. When I say miss the tach drops 300 rpm sort of like someone is shutting off the fuel then turning it back on. I figured it was either a reduction of fuel, or air being prevented from entering the engine. On a whim I disconnected the vacuum actuator on the EGR intake flap and wired it open, and it now runs smooth as silk with the same operating conditions present as before. What would cause the flap to cycle enough to cause a perturbation in the engine? Would it be one of the vacuum amplifiers/controllers, or EGR valve. By the way I now have a CEL on probably due to a reduction of intake vacuum as seen by the manifold pressure sensor. Thanks in advance

It is probably the transducer. I'm not certain of the parameters of the EGR transducer but do know that on the turbo engine the ECU looks for a voltage drop at the wastegate transducer to occur after 10 seconds of boost; I expect the EGR operates in a similar fashion.

There is a EGR delete avail on the forum for the 606.912 that seems to work well with no codes.

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Terry Allison
N. Calif. & Boca Chica, Panama

09' E320 Bluetec 77k (USA)
09' Hyundai Santa Fe Diesel 48k (S.A.)

You might want to remove the EGR and try cleaning it out, it just might be sticking partially open or closed. There are also 2 other transducers in the intake manifold. If you are up to it, remove the intake, be very careful when removing the transducers as to not break a wire, then have the manifold cleaned out. Most machine shops can boil the gunk out of it.

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Dennis
2006 E320 CDI Black/Black Leather. Nav, HTD Seats HK stereo 32000 miles.
2000 VW Passat 1.8t 300,000 miles as of Dec 09, 2009 original owner
1997 E300d Silver 300,000 miles As of Jan 05, 2010
3rd owner SOLD