nick280c

when I stop at a stop light my cars seems to be jerking forward when I let up on the brake a bit. when the brake is firmly pressed it is OK but if I let up at all it is seems jerky. If I was to let the car move without any gas it is real noticable. Please help, oh yeah I just bought the car but didn't notice it really until today.

simplexchange

Do you feel like the car is underpowered when accelerating, like when getting on a freeway?

nick280c

yes a little bit, I detailed the engine a couple days ago and I think I might have gotten water in one of the spark plugs and is fouling out that cylincer? that is almost what if feels like is a cylinder that isn't hitting

RunInColorado

If a cylinder is missing or even if you have low compression on one, you will notice. If its missing, the whole engine and car vibrates and rattles. The car will then lack alot of the power it use to have. I had this happen on a 190D when an injector was leaking (as in diesel going all over the engine, not into the cylinder). I could floor it and swear it barely moved at all. It rattles and vibrates badly at all speeds.

With low compression the car tends to feel "nervous." It shakes and stutters a bit but still has most of the power. It also tends to do it at idle vs at speed.

Hope that helps.

040mercedes

I think I have the same problem, but see if you can answer this: Mine only does it occasionally, after you have mashed on the the gas and the car kicks down a gear and starts accelerating quickly, right after that, it will start the "shaking, and misfire" However, it does this only on rare occasions, not all the time. Then to top that off, I can shut the car off at a traffic light and immediately turn it on and it stops. It runs fine again. If anyone can tell me exactly what is wrong there, you're my hero.

Suzdalov

I have exactly the same problem............it shakes and misfires, but if you stop and restart the car .........it works fine then after that..................I took it to a dealer and they found something like ......"HFM current voltage too low"..........that's the fouldt code for this issue they think anyway....................but they can't figure out what causes the loo voltage...............loo voltage causes misfire and hence loss of power on acceleration and viabration when driving and ideling. They also mentioned that this current somehow related to the fueling sytem and that could cause this problem also..............................

People...................any suggestions please let me know..................

040mercedes

Suz,

I'm still trying to figure this one out....I pm'd you my response, hopefully that will at least point me in the right direction. The plugs wires, and blaster coils(or distributor) may be a good place to start, considering its low voltage that seems to be an issue.

P.S. If you happen to find a solution yourself, PM me with the answer. In the meantime, I'm still working on it.

Suzdalov

yesterday.................I washed my engine and the problem is even worse now..............I assume I have bad wires 'cos when my mech looked at them last time onw was a little burned and he had to put some tape on it.........., but I guess it still shoots the electricity through it or, or may be it even burned agained now the problem doesn't go away after I restart it.........................I'm getting the new wires on Monday..............and will let you guys know how it went.............................................. .........

040mercedes

washing your engine......bad idea. Thats definatley a no-no with benz's. That will make your car run really crappy because your plugs got filled with water. This seems to be a common error with benz owners.

Suzdalov

The problem was there before I washed it..................and when I washed it got worse...............and it's back to what it used to be

040mercedes

it got worse because there was water sitting down with your plugs, hense your car running worse temporarily, the water had to dry. No big deal now, but you might want to invest in some new plugs here soon.

Suzdalov

installed new wires yesterday and checked the coil packs .............all fine............If I pull out a coil pack when the engine is on.........you can see a big difference right away.......so it's the coils nor the wires as I've just changed those............still it looses alot of power and like I mentioned before the codes are "no current", and "low voltage".......the dealer said it's draining a lot of power some where but they have to do some extensive testing which is gonna cost alot............and I don't have the money at the moment to spend on that ....it's not any of the sensors 'cos when I disconect them I can see the difference and that they are functioning...............

Question:...............if some one hooked up to the computer and ****ed around with it........and changed the mixture or some kind of setting in there, can it start behaving the way i described earlier ....shaking and ****.......and loss of power......also ....can a fuel filter be a problem if it's never been changed...........however..........it still seems to me as the problem is electrical.....................I know that my battery puts out 14.5 volts .....can that be a proble............I mean it can be a problem if it doesn't put out enough....e.g 11.5 volts, but what if it puts out more......? ....also I could get rid of the shaking if I restarted the engine..............not anymore.......it doesn't go away at all and it has no power at all.............takes me 5 minutes to get to 50 km per hour...............not as bad though when you drive at a higher speed ......................any clues guys......................

040mercedes

damn....it sounds like you've done a lot. I'm at a complete loss. I've often wondered if the problem could be a fuel pump or fuel filter also. But you're right, that wouldn't make sense if the problem is electrical.....this whole issue with these cars is painfully confusing, I'll keep doing some research in the meantime.

Suzdalov

Thanks............................................ ......