CPS or something else ?!
I had this issue recently where my car suddenly act so weird and start accelerating and breaking at the same time!? And sometimes hard to start engine, it goes after i turn it off and turn it on again.
I tried to search the net about what is exactly going on and i found some people that have exactly the same problem, but the bigger issue i ahve is that every one have different kind of fix !!
I am not being lazy and want an instant fix but i want to narrow the options for what to look into and maybe the cause of this frustrating issue.
I recently put a new fuel sending unit because of the infamous fuel leak, any chance it maybe related ?? Or is it the CPS as most of the people say ??
i would really appreciate it any help from you guys, thanks a lot.
Last edited by Venom55; Sep 1, 2017 at 11:01 AM. Reason: Correction
Start by borrowing an OBDII scanner from your local auto parts store and see what codes come back and go from there.




P2046 O2 sensor signal upstream implausible
P200B-1 Camshaft Hall effect sensor
P207E-1 Catalytic converter efficiency low
My two cents? Start with the MAP sensor, then the camshaft sensor, then look at the O2 sensor and then the cat. If it's the MAP sensor, that will cause all of the other codes.
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Thanks for the information really appreciate it. So i took it to my mechanic and he told me that he cleaned the MAP and fixed something in it ( i dont know what he fixed exactly), he also changed the number 4 the coil and the wire after it came with the codes, he also cleaned the injectors.
I took the car after he fixed the stuff and the only thing it got fixed is the shaking when u are in idle maybe it was caused by the misifre of the bad coil, and i was really happy until later when i drove it for a while to see if the real problem is gone, i gave it WOT and damn there was no power like absolutely no power, i thought maybe i didnt press the gas properly (which absolutely ridiculous) but i am trying to make my self feel better because of the money I paid.
Later after 30-40 mins of driving the car i hit WOT again and the same exact problem is there, it is like suddenly someome hit the brake without warning and the car wont move until i remove my foot and hit it again softly very softly and it barely reaxh 30 kilos per hour. !!! I hit it WOT again and the car feels like it is choked if i can say.
I hope I described exactly what i was facing and actually i reas a lot of posts with the same symptoms i am having.
I really really love the car and i want to drive for a long time.
Do u think u have a clearer idea about it now.??
Btw the throttle body was opened and was cleaned.
Thanks for the answer and i hope i get the permanent fix soon.
Last edited by Venom55; Sep 7, 2017 at 03:35 PM. Reason: Correction
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As StarvingArtist stated, you replace MAP sensors, you do not clean them. If the MAP sensor faults, the ECU will default to "limp-home" mode and do everything in the program to keep you from blowing up your engine. Don't try to clean the MAP sensor; replace it.
Basic checks now:
-fuel pressure at idle should be 78-82 psi (5.4 -5.6 Bar).
-read codes; a misfiring cylinder will provide the code for the misfiring cylinder. The code is P030x with x=cylinder that is misfiring. i.e. P0301 means cylinder #1 is misfiring. P0302 and P0306 means cylinders 2 and 6 are misfiring.
-the misfire code will also come with a warning "misfire, damages TWC" (three-way catalytic converter)
-it could be as simple as cheap spark plugs with eroded electrodes (that was the cause on my car); or spark plug wires in poor condition.
-I will say it again. If the engine is misfiring, the ECU will throw codes! No ifs, ands, or buts. It will throw codes and it will tell you which cylinders are misfiring. At that time the usual suspects are spark plugs, wires, coils. Far less likely is a wiring harness problem.
-Have you seen the P030x codes yourself?
-Since your car failed accelerating, you will have codes stored. Pull them. If the MAP sensor is there again, replace it.
Thanks fir all thise who helped me with this issue I really appreciate it guys.
Keep more than 1/4 tank of fuel in the tank and drive happy.




Read this:
https://mbworld.org/forums/w211-amg/...intenance.html
Very important (since I do not know where you are located) that you used the proper adapter cables with the fuel pump and fuel filter. Later model fuel pumps reversed the power/ground connection on one of the two pumps; if you do not have the proper adapter cable, one pump runs backward and fuel pressure is too low.
Thank you for posting the resolution of your car's problem.


