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Discussion Starter · #1 ·
Stepping on the gas peddle, the car slightly lunges and immediately bogs down from the load on the engine. The car crawls until it reaches a little over 1000 RPMs and then picks up about how it should. The problem is intermittent. Sometimes it takes 10 seconds to reach the RPM at which the car picks up...and sometimes there is NO drag when accelerating. It doesn't SEEM to be ambient temperature dependant, nor dependant on engine temperature. I just replaced the fuel pump and fuel pump relay (brand new fuel filter already present). I've also replaced the catalytic converter, pre catalytic converter, all transmission fluids (including draining the torque converter), idle control valve/warm up regulator, and replaced the fuel distributor with one from another car to see if that was the problem. No difference. Is there anything under my fuse box that could be related to my engine sensing RPMs and adjusting power accordingly? I know one fuse under there even controls electronics for the transmission. Oh yeah, also my temperature and oil pressure gauges broke about a month ago. About that same time I noticed that the car's dead spot problem was much worse (it took longer to reach the 1000 RPM mark and pick up speed) and no amount of pedal pressing would make my car downshift, at ANY speed. The broken temperature gauge had my auxillary cooling fan running constantly. I unplugged it and the lightened ELECTRICAL load seems to have brought my dead spot problem back to the severity it was at before. How is this possible??
 

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Discussion Starter · #3 ·
thanks for the info. There are a couple sensors mentioned there that my mechanic has never brought up before. Is there a way I can see if the throttle body is in good condition myself?
 

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1991 300 SE
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You can see the throttle body under the air cleaner – use a rag with carb cleaner and clean inside the body and around the air plate.
 

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Discussion Starter · #7 ·
no. is that something that would cause initial hesitation but not at higher speeds? Is it a very labor intensive part to replace? how much do they run?
 

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1991 300 SE
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Hang on, it may or may not be the coil – work through the list first. Once you finish with the list move on to the less common stuff. You don’t want to throw $$$$$$ parts at it if all that’s needed is a good cleaning of a part or adjustment.
 

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1990 300SE
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1,466 Posts
Well, the ignition coil is a pretty common replacement. More like an investment, instead of waiting for it to break.
 

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Discussion Starter · #10 ·
RE: Hang on, it may or may not be the coil – work through the list first. Once you finish with the list move on to the less common stuff. You don’t want to throw $$$$$$ parts at it if all that’s needed is a good cleaning of a part or adjustment.



This problem has been getting progressively worse for almost a year now. I'm pretty sure it's a very uncommon solution i'm looking for or my mechanic would've found it by now. I've actually been to a FEW mechanics. You see the list of items i've replaced. I think there are a few more that I just can't remember...like the 02 sensor and a vacuum line. Thanks for your help. I'll post more after there is progress with ruling out items.
 
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