I drive a 2001 CLK55 with 55000 miles.
Only [ast problems are gas guage stopped working. (i plan on having both fuel sending units changed shortly)

Heres the current problem:

I entered the freeway at a pretty good rate. (kinda stomped on it). 2 miles later at my exit, my CEL came on, but car was running fine. When I got to stop light, car was stumbling in idle. Continued driving and car smoothed out when out of idle. Stopped car again, idle was worse. Then car decided not to start. (Car would start sometimes, but would run real rough and then die). No previous occurances at all mind you.

It almost acts like it is out of gas, of course that will be my first objective is to put some gas in just to make sure. (I dont believe that it is empty)

I ordered a crankshaft position sensor as a precaution tonight, it should be here day after tomorrow.

Questions:

1) Could running out of gas actually throw a CEL? I will read codes tomorrow, but maybe cause a misfire or a fault MAF if its not getting adequate fuel at the time of running out?

2) I've read that others have had very similar experiences and have changed the CPS to fix. However, their problems seem to go away when engine cools, mine does not. Is it possible that the CPS **** the bed completley instead of slowing going bad as most have described?

3) Being as I already have faulty fuel sending unit, I go on resetting the trip odometer to time my fill ups (havent had a problem yet). I just fill up when my trip gets close to 250. Is it possible that this problem is progressive? ie: The sending unit telling the pump to stop when Im not really full. Therefore, I actually did run out of gas because it never completely filled?

4)Anyone know a reliable INDY in the bay area, NorCal?

5) Any suggestions would be greatly appreciated.

Thank you all very much.

John

 

I've had this same issue when I first bought my car...I'm willing to bet it's your MAF. This would be the first thing I'd check if I was you. Don't pay the dealer 350+ for this part (not including labor). Go here to this place (autohausaz.com) and buy it for 168.80! Here's the actual link for your year and model:

http://www.autohausaz.com/search/pro...0Mass%20Sensor

There are some instructions how to remove the MAF yourself if your interested I just have to find the weblink first. Good Luck!

 

Thank you for your response. That was my second guess. I just ordered the CPS and the fuel filter from AutohausAZ last night. If that does not work... MAF was next. I'll keep you posted. Going out of town for a week anyway, so I can wait on the part.

 

Ok, I got home from work. Put gas in just to make absolutely sure.
Read the codes from the OBD II, they were for cyl 1, 5, and 6 misfires. I cleared codes and they returned. The car would then return to normal sporatically and then the misfires would return.
Any thoughts? I've pretty much ruled out plugs, wires, coil packs as I cannot imagine that much equipment failing at the same time.
CPS? MAF? ECU? Timing belt? Vacuum leak?

 

Trust me on this one....I'm 99.9% sure it's the MAF! I had the same exact issue. Here's what happened. After driving it on a normal day the CEL came on. I took it to the dealer and he said the gas cap was loose (Liar) he didn't want to tell me it was something else because I had just bought the car. So anyway, the problem did not come back until a few days later after driving it hard. I came to a stop light and the car felt hesitant as if I was about to run out of gas....I thought this was extremely odd being that I had a half tank. So my next thought was maybe I put in some bad gas...so I tried to drive as much as I could to burn out the bad gas but the car just wasn't showing power....very sluggish and the idle would not hold at all, it was all over the place! So finally my mbworld buds helped me out (Ohlord, Chappy and the rest gave me some pointers on what to check etc. Sure enough I went under the hood and took out the old MAF..cleaned it with some CRC stuff, let it dry and revved it up...but the problem was still there. Then I went to go get a OBD ll code reader....got my code and sure enough it was the MAF. Cleaning it didn't work for me as it did for others so I bought a new one from autohausaz.com. Removed the old and installed the new one and haven't looked back since. Now it could be something else and perhaps a lot worst but for the cost and the symptoms that you have I'll say check that first and foremost. Good luck with your decision

 

Thanks for your response.

I ordered the CPS, MAF, and fuel filter last night. I would rather 'shotgun' these parts in prior to a dealer visit. Relatively inexpensive with a high mortality rate anyway. I'll call it preventative maintenance. Later on I plan on quadruple checking for vacuum leaks or loose connections and the like.

 

MAF sensor FTW.

Ive seen intermittent problems too many times (Aircraft Mechanic by trade) to start jumping up and down, but so far so good. I will update in a few days. I still plan on checking my fuel pressure at the rail to verify adequated fuel delivery. Thanks again, Martymar

Looks like the MAF crapped so hard it didnt even code itself.

John

 

Ok, I was out of town for a week. Came back. Add another 3 days to the clock. Looks like we're good.

1. Cleaned Cam Position sensor.
2. Replaced MAF.

 

EXCELLENT! I was pretty sure it was the MAF...that seems to be the biggest issue with our cars (aside from any major issues). I'm glad I was able to help. Other guys in this forum has helped me out tremendously so I had to show love back.

 

Do you think the Green Filters were part of the MAF issue? I've owned my 55 for over 6 years/40K miles and no issues - but I'm running stock air filters.

 

interesting thought Chappy, I put in Greens a while back but it has been almost 6k miles. My first issue just happened this weekend. Drove down to the hardware store, got back in and it would not start. Tried a couple times then waited to see if it just needed to sit. Checked the fuel pump fuse just in case and it was good then it fired up. So it would have sat for 20 min maybe long enough for the CPS to cool if that is the issue. What is strange is the hardware shop is about 2 miles so things could not have gotten that hot. I will have to keep an eye out and see if it is the MAF or CPS.

 

Having been around awhile I've come to the conclusion that neither green filters nor K*N are worth the bother. These mods are not risk free, and the performance gains are not huge.

 

I've been running Green Air Filters (model #2240) in my CLKs for nearly 7 years. In fact I have 2 that are "drying" in my garage as we speak waiting to be re-installed into the 55. I over-oiled it a bit so, I'm letting it dry for a few days before re-installing as a precaution. When re-oiling, the trick is to very lightly spray it once or twice on both sides. Don't be tempted into spraying it any more. Then let it air dry for as long as you can and re-install. The instructions are not very specific as to how long to wait for drying or what "not over oiling" means.