bpdover

I have this problem all the sudden, when I start the car in the morning there is a small shaking/rough idling, not a hard shake, but kind of like a little instant lose of power (in the engine, not electrical), this also happens intermittently when I get to a traffic light, all the injectors are new (about 6 month) and the car accelerates great on the run and the kick-down is good, but sometimes it feels like if there is not enough air or gas getting to the system in time (that kind of rough idle), I also changed the fuel filter about 7-8 months ago. What got me puzzled is that sometimes when I get to a traffic light, idle is really smooth; that you can’t tell the car is running.

Has anybody had this before?

CLKBSVegas

fuel pump maybe? I had similar symptoms with my old BMW 530. I changed the fuel filer, injectors, then did a full tune up (it was about time anyway)...but the problem ended up being the fuel pump.

Check it out...cause if it goes you will be stranded at next start up

teky

check all the spark plugs are ok, its not uncommon for these silky smooth engines to run with one out

charliev68

spark plug connectors, might be just one or two that is bad. i had my #6 one go bad and it did what you are describing. on my car (w208 430) it never gave a check engine light. dealer diagnosed the problem and it never did it agian. hope this helps.

scorchie

I am not sure what year your car is, but on my SL500 with an M119 engine, I had a similar problem that started after the car was less than one year old. It never got fixed, because no one else would acknowledge that such a small shake existed. I had to do demonstrations like hold a cup of water in the car and let the shake disturb the surface of the water, and it was still not acknowledged by the service people. I noticed it because I drove the car every day and a change in the way it ran was really apparent to me.

Now, I've learned that depending on the year, and engine management, and actual engine, there are a lot of things to do on the car that sometimes never get done by service people. Such as normalization procedures, which affect the idle. Or flywheel and other adaptations. Make sure that all the things specific for your car are being done (such as if the battery is disconnected, there is a whole checklist of things that need to be done).

-s-

bpdover

Hi guys,

Just a follow up, I replace all of the sparks plugs with the bosh platinum 2 (2 prones) and the shaking went away, althought I did notice that one distributor rotor had a little build-up on one end, as if a little metal dust was melted on the rotor contact, but the distributor cap looked fine, I cleaned both rotors and caps, just as a prevention, so I can't really said if it was the plugs (which needed changing anyways) or the little dust on the rotor cap, but I'm happy it just went away.

thanks for all your input.
Bis

s0vietbenz

motor mounts