CL600CK60V12

I have been getting a random P0300 ("multiple misfire") code and clearing it. I have new sparkplugs and new coil packs.

Car runs fine and from what I have read so far, adding some fuel system cleaner like "Seafoam" might help. Before I do that , I wanted to ask if anyone had this problem with the CL?

Thank you,

S.

mf219

no misfire problems here, but I'd be careful what ya dump into it. the only non MB fuel additive that the manufacturer approves (that I know of) is Techron by Chevron. I've used it several times

tusabes

Multiple misfire might be the transformer between the coils

Or another bad coil

biker349

i go for the ignition module, transformer.

CL600CK60V12

I have brand new spark plugs, brand new coil packs, drove car for 1200+ miles, no loss in power, no weird noises. Added techron twice on half-empty tank, then I added Seafoam after that. Car responds even better after two techrons and seafoam.

Car runs great. After I reset the check engine code, it comes up again while driving without loss in power or any other indications.

I won't be able to take the car to service for another month. Thank you for your suggestions, I will add that to the list for checkup.

Btw, I am getting 19.6mpg with the CL (spirited and "normal" hwy driving combined . If you are not taking your CL to the open road, you are not fully enjoying it It is literally awesome - it inspires awe and it is a bit terrifying

biker349

you may have to use a star system to clear the code, or possibly disconnect the battery for an hour and see if that resets the code. remember to reset all functions if you disconnect battery.

CL600CK60V12

I can clear the code with Actron but the P300 code (random misfire) comes back after a while ("P0300 Mod $10") while driving but without any loss of power.

Now that you mention the battery: I did have the new battery installed just before the road trip because the old one was too weak.

In May, I took the CL600 on a road trip. On the first leg of 1300 miles, I poured two bottles of Techron and two bottles of Seafoam - this improved the throttle response and car drives like a dream. Absolutely no hesitation. Frightening acceleration

The beast is getting 19.6mpg, 400-mile range on a full tank.

In fact, since running through the second bottle of "Seafoam", the code has been cleared and did not come back for a week now - knock on wood.

This year, I am putting some miles on this thing - no more "garage queen".

tusabes

These cars do need to be driven

biker349

did you put the sea foam in the fuel tank?

CL600CK60V12

yes - I put "Seafoam" in the fuel tank.

CL600CK60V12

Also, this car does not like humidity and I am still struggling how to keep it away from electrical components. Even though ESP is enclosed in the plastic box under the hood, that box is not airtight. It is the worst place for sensitive electronics.

It also does not like heat. Driving in 75F+ weather leads to "heat soak". Even though I read the extensive thread about pumps and heat exchangers, it is still not clear to me which pump/heat exchanger combination would circulate enough coolant to reduce heat soak. Renntech offers a cooling upgrade but I cannot find any real data on how effective it is.

grane

I would stick with regular use of Chevron Techron. They spent the money to pass the certification test. I called Seafoam and BG that some dealers use; they have no plans to seek MB certfication

After a period of non-driving, I had a stumble in one cylinder in the CL55. I filled up with Shell 93 and two TechronsI'm told dealer have hide the BG equiptment when the MB factory service folks come buy eek:

Regular use of Techron beats buying spark packs for no reason.

CL600CK60V12

I drove the CL for 3000+ miles recently and used two bottles of 20oz Techron and three bottles of Seafoam.

Car responds much better now and it sounds much more aggressive. Fuel economy improved also.

I added Techron/Seafoam to half a tank each time and drove until the needle was half in the "red", then filled up, drove to half a tank, repeat the process.