'03 CLK320 w/Slight hesitation, noise around 40 mph and 2000 rpm with light throttle

[tim757]

About 3 weeks ago I had MB of Coral Gables do the following services:

A svc, serpentine belt replacement, fuel injector service, radiator flush.

Starting about 5 days ago, we began to notice a slight hesitation, very light vibration and very faint noise under light throttle around 40 mph and 2000 rpm. At higher cruise speeds, under heavy acceleration, and coasting, everything is perfectly normal.

I plan to take it in again Thursday, but wanted to get some ideas first.

Anyone?

Thank you.

[unitfreebie]

Could be a lot of things causing those symptoms... could you be more specific???

Have you done the major 60,000 miles service? Change fuel filter, air filters???

In older years W210 (6 cyl) around 2000 year, the MAS sensor went out around 65,000 miles! but will throw some ambiguous code like 170.

Is the serpentine belt properly tensioned?

Hope that helps !

[tim757]

My tech says it could be the fuel filter because it is only happening at very light throttle settings. The car has 53,000 miles on it. They did replace the serpentine belt 3 weeks ago at the A svc, so I will add the tension to the list of things to check tomorrow. The MAF sensor was replaced last year.
Thank you.

[unitfreebie]

Yes, definitely change the fuel filter to, which is cheap and simple, to eliminate the other possiblities...

Did you go to a new gas station to fill up just before the problem occurred? It doesn't take much to screw things up if the gas is bad...

Also what exactly is the Fuel Injection Service??? Is it just a pint of injector cleaner in the gas tank or something else??? Maybe it did a good job and dislodged some carbon particles that got stuck in the spark plugs? In which case, the idle would be rough... You might pull the plug in the last cylinder and inspect it... if it is anything but a nice light brownish color, change the plugs to the Bosch Platinum +4 plugs for extra hot spark to give complete combustion.

While you are at it... have your tech change your automatic transmission oil and filter!!! Don't believe that 100,000 Miles service internal crap unless you have $5,000 for a new rebuilt 5 speed automatic transmission!

Let us know what fixed the problem -

[tim757]

2 days at the dealer and no one has a clue yet...

[unitfreebie]

uh.. oh...!! Git ready for a big bill!!!

[Dodge CLK]

Did you every get to the bottom of this? I also have a 320CLK with a buzzing kind of vibration from under the car at about 40mph under light throttle,however i dont notice any hesitation in performance.
Any help is appreciated.

Dave

[unitfreebie]

Please PM him, get the fix and post it back here so we can close this thread!

Thanks..

[navydave]

I'm having the same thing in my new (to me) 2003. Buzzing kind of vibration, a bit like driving over rumble strips, under light acceleration, right around the 2-3 or 3-4 upshift.

[navydave]

I PM'ed and he doesn't know what the problem is...he's waiting for the next service.
I'm not waiting around for the trans to grenade on me, and whenever I get a car I do a baseline fluid change, so I'm having them drop the pan and change the fluids and filters.
When I know what the deal is I'll report back.