Hard acceleration puts car in soft limp mode
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Joined: Mar 2013
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99 E320 4Matic Wagon
Hard acceleration puts car in soft limp mode
My 99 e320 wagon with 106K will start to misfire and goes into the soft limp home mode whenever I accelerate hard, and by hard I mean pedal to the floor. usually starts about 4000 ripms, maybe 3rd gear. Normal acceleration, pedal halfway down causes no problems at all. This was discovered by mechanic when I took the vehicle in to have the transmission fluid changed, and a recent "check engine light had come on. Codes showed misfires on every cylinder, and a speed sensor code. Changed plugs and wires, seemed to take care of misfire codes. Mechanic wants to trouble shoot more, but doesn't seem like he knows where to go. At $120 @ hour I'd like a little more definite idea of where to look. This sounds like the speed sensor conductor plate issue I've read about here. Advice and criticism accepted
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Joined: Feb 2013
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From: central portugal
c124 124.051
i had a simaliar problem when i bought my car,codes were for maf ,changed that no good,mercedes dealer thought it was a blocked cat or section of exhaust,they then discovered that the air filter inlet,where it sucks the air in,next to the rad,was closing under accelaration,needed reattaching next to the rad,male and female parts,soft rubber pipe connects to rigid plastic housing by the radiator and stops itself sucking shut
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Joined: Mar 2013
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99 E320 4Matic Wagon
Thanks Matt72 and Plutoe
Matt I'll take a look at that once my wife gets back. Be nice to think it was a simple fix like that. Plutoe thanks for the perspective. Just got back from a more detailed chat with the Mechanic, and your right he can't figure out both the misfires and limp mode. Said the limp mode would keep you in same gear, but has no control over misfires that is an ECM problem, maybe. Also said there was a transmission temp code he pulled out. I posted the question to see if I could increase my knowledge of the interplay between these systems, and to see how deep his knowledge was. This is my first time dealing with his shop, and the misfires and limp home mode were not issues I had experienced with the vehicle, but I had never tried to accelerate the car that hard. Try to find some time next week to get it back to them. Thanks again.
