Had a check engine light come on after the car suffered from a rather noticeable loss of power. The engine revs easily in neutral, yet the transmission is hesitant in shifting and when in drive, it lags tremendously in acceleration, as if eight of my cylinders deactivated. Went through the whole slew of basic checks, disconnected the battery, transmission reset, and even a top notch fuel system cleaner. I suspect an issue with my MAF, since there is no sulfuric odor indicating a catalyst problem. My car has always been thoroughly and extensively maintained, and is stock barring a high-flow filter upgrade. No, I have not re-oiled the filter, since this is a common cause of MAF failure. Having spent $2G in repairs these past few months, I am getting fed up. What do you guys think it can be?

 

I use to have the same problem..... After change the O2 Oxygen Sensors it fix..... hope this help & good luck.....

 

Thank you, I'll have to try that out.

 

i had something similar happen (same feeling) to my sl320 and some oil had gotten in one of sparkplugs and needed to change out the gasket since it leaked

 

75% probability that it is one or both of the MAF's.

But if cleaning or replacing those doesn't correct the problem, then I would go right to the pre-cat O2 sensors. If you end up needing any replaced, then just replace all of them (including the post-cats at that point)...because once one starts failing the rest aren't far behind, and you can consolidate the trips to the dealer and save on labor by just taking care of all of them at once.

These little gadgets just crap out and require replacement after awhile. The O2 sensors bake in some outrageous heat and die from it eventually, and the MAF's are stuck in a tube in a constant 100mph stream of air, so they accumulate crap as well. If these are original to the vehicle, it's just getting to be time to replace them. Routine maintenance.

 

Two O2 Sensors and 12 Spark Plugs...in the shop right now...can't wait to get it back.

 

Please trust me on this one and have them change out the other 2 while they're already messing with it. They all tend to start failing at about the same time, and that will save you an inevitable return trip to deal with it later.

Also, good idea on the plugs. You will notice a nice positive difference from that.

 

crazy shot, but that happened to one of our vehicles. turns out it was just contaminated oil. oil change fixed it.

 

did the 02 sensors and plugs fix it?

you werent in limp-home mode by any chance, were you?

 

All spark plugs were changed along with the O2 sensors. The misfire has been corrected. Still, there was a severe power loss. I went ahead and had full diagnostics done...turns out to be two clogged cats.

My indy quoted me $3G...for cats...I had to place the phone down for a good laugh, and picked up the car. Going to specialty exhaust shop when I get back to town, a place where people have some sense.

Apparently my indy got fed up with my common sense, granted that I only pay him for labor and purchase OEM parts myself, for a third of the cost mind you. Oh well, time to find a new one.

 

i'm having a similar problem that a dealer diagnostic showed as MAF sensor on my 500; check engine light was/is only intermittent. my indy guy took the car, found a vacuum leak somewhere and fixed it, which lasted a few days and now the light is on much less often but there's a definite power lag/drag going on that makes the car much less of a pleasure to drive. it seems a lot heavier than it used to, if you know what i mean.

i looked at the MAF online, and it appears to be a pretty simple fix i can do at home. if i replace it myself, will the damn light keep coming on -- will i have to take the car somewhere to have the diagnostic system reset?

 

dude, get racing cats from magnaflow for like 250 each. plus they add hp and sounds great!

Mark

 

Hey, Mongoose,

A few members are asking about "limp mode" every once and a while. I just got mine last fall, and have had at least my share of these experiences. I've just about figured out how the stuff works, and it sure sounds to me like that problem lies at the base of a lot of these "power loss" issues. When a member says things like loosing any acceleration, or, the transmission starts shifting funny, it just makes me look in one direction: The AST, or ABS, or DS type problems. Sure, it can be the other things as well: MAF sensors, plugs, cat-mufflers, etc. But, my feeling is that until all of us know why AST is doing the things its doing, all of us will still be trying anything we can to make the car at least run Better. I mean, after all this is supposed to be a performance car, and that should not include "pain in the AST performance!" What do you think?

Brick

 

I am considering either those or Edelbrock cats. Would love to go with a catalyst delete, but my the car needs to undergo emissions testing in a few weeks. Also ordered some new rotors and pads, which arrived the other day. Car is getting a nice amount of work done. I've had it with this recent lack of performance, so time to get it back, blast my pipes completely clean on the highway in the middle of the night, and spent the following day washing the wheels and body, waxing it, and throughly clean the interior.

 

Limp Mode-

my car went into limp mode 1 time, and it was as i was pulling into the shop. the battery light came on, and a few others. all i did was replace the alternator.


the signs when you have bad cats usually are; loss of pawer at high RPM, car has trouble going over a certain rev. and one of the last things, is that you will get a bad odor from the tail pipe of the car (usually somthing like eggs) if these are not taken care of, the cats can get so clogged, that they ignite.

Mark

 

i herd that Flowmaster makes them for edelbrock. but that could be false info. i have had the flowmasters on my SL and the E500 before we sold it, and it really adds that little bit to the car!

 

Two new direct replacement cats installed, and new 02 Sensors with them. Still waiting for the ECU to fully adjust to the higher flow rate but the power is back. A nice added bonus is that the car sounds noticeably meaner now, much better than the muted stock sound.

 

Which cats did you end up going with? Also, what was your total bill for the parts + installation?

 

I just had the same thing happen to me!

I had just a series of incidents that cracked me up...like when they quoted me $1600 just for new OEM pads and rotors, out of which $1000 of it was parts.

Then I showed up with Silver-Arrow drilled rotors, full ceramic pads, and a set of custom made stainless brake lines to go along with them, along with all the paste, wear sensors, etc., that I got all online for around $500 total. They were not pleased. Same thing happened with the water pump, $600 price quote from the indy vs. I got it for $240. Same thing with 100 other things.

So last time I was in, they cornered me and said "We are changing our policy and will no longer accept parts from the customer". I asked why, and they said "we can't warranty them". I said "no problem, they're OEM parts, they come with a manufacturer's warranty....and if you're still worried, then I'll be happy to sign a waiver". They responded "Sorry, that is our new policy". Lol, at that point it was obvious that $$$ was the real issue, and I told them "Well, then I'm sorry, but since that will add around $5k to my annual maintenance bills, you're going to lose this customer. You always quote me more than the dealer would for parts, and your labor rates aren't far behind...and at least there I get a Benz loaner car in the meantime...". The guy said "Well if that's how you feel, then fine".

I have been using that shop since 2001 or so, when I had my old '81 300SD. Worst part is, they have probably made $20k - $30k off maintaining my cars since then, and I referred a ton of friends to them as well. Heck, my friend Roy took his Silver Shadow in to them, and the brake job alone was $8k. Way to treat a loyal customer...

Anyway, I have an appointment on Monday with a new one who comes highly recommended, to track down a smattering of annoyances. We will see how he is.

 

My friend, finding an honest mechanic is akin to finding an honest politician. Well, maybe not that bad but you get the idea.

I just had all my pads and rotors replaced. 350 for parts, all OEM, another 250 for labor. Verbatim they gave me the policy change speech. I can't say anything bad about the quality of their work, as it always has been top notch, but it gets pricey, especially considering that it can be had at a fraction of the price.

DEC direct fit replacements, paid about $350 a cat, free shipping. Another $350 for installation, testing, etc. So much for $3G...and the sound is improved as well. Found another guy now, not MB exclusive but handles many foreign cars. Has a sense of humor and could care less where I get the parts from.

 

My apologies, I was mistaken in assuming a much higher flow rate over OEM, as I stated in my post the other day. After some discussion today with my mechanic, the improved flow is marginal, maybe a few horsepower if I'm lucky. It's the new sound that has me happy.

 

That's nuts that your guy gave you the same speech! There must be a convention or something where these guys get together and share all the different ways to screw the customer. I couldn't believe my ears when I heard that stupid speech from them...I thought it was so ridiculous, and frankly it was something of an insult to my intelligence. It's clearly all about the money, so the least they could do was just come out and admit it...lol

I think what happened is that, for years and years, the entire marketplace for Mercedes parts was dominated by two entities: WorldPac, and the MBUSA parts network. Neither of them would sell direct to consumers, rather you had to have a commercial shop or a dealership and then get a distribution license from WP and MBParts before they would sell anything to you.

So basically it was a captive market, and it stayed that way until around 2001/2002. Then, parts.com started cobbling together a network of dealers who wanted some extra business and would agree to sell any part in the EPC direct to consumers for a couple bucks over their cost. Autohausaz, RockAuto, and the rest also came on the scene around then, along with scads of others. So all of a sudden, you could order parts for the same price as your mechanic, or less.

Over the ensuing 5 or 6 years, people got wise to the 200%-300% (or more) markup on foreign car parts and just started buying them direct on the internet. As of 2008, now it has come to the point where they probably see a significant chunk of their customers bringing in their own parts. This eliminated a nice little profit machine for the independent shops, where they could make several hundred dollars off each customer for nothing more than spending 5 minutes on the phone.

Now the mechanics, pissed at their lost revenue, are trying to turn the market back around the same as the RIAA did when they began suing online music downloaders, with the absurd idea refusing to take any job unless they provide the parts. It has nothing to do with warranties or anything else...the truth is that they're just trying to get their ridiculously high markup back. It's obnoxious and I won't participate in that.

I can order anything I need for my car online in 5 minutes or less, and since they do it many times a day more than I do, I'm sure it probably doesn't take the Indy even that long. So I don't see why that minor service entitles him to several hundred dollars worth of my money on each visit, especially when Indys generally are already charging almost as much as the dealer does these days. These people need to quit trying to fight the internet, it won't work.

And unlike the RIAA, which has like 10 or 12 major recording companies who are members, you can't get all the indys together in a room, and you would never be able to get the 20+ different mercedes shops in every city to agree not to accept parts they don't provide. Meaning, someone will always be willing to do the work, because there is a lot of competition. So, I will just go along to the next guy, and when he acts up, I'll go to yet another.

It's a shame, really, because they are bound to run off a lot of customers in the end.

 

That's some interesting info; I didn't know the background behind this parts issue. However, I assume (and correct me if I am wrong) that you and I are among a small percentage of customers who use some sense when it comes to maintaining out of warranty MB's. Most just drop it off and say "fix it," no?

 

Well, there's a sea-change going on I think. That's probably why all the indys are starting to get snarky about people bringing their own parts. I think it used to be how you describe it, where people just let them handle everything...at a significant profit to themselves.

But these days, everyone is computer literate, and when confronted with a large repair bill I think the first instinct must be to go online and verify the price. That will wind up with them bringing their own parts, once they see what the same thing goes for on the internet...

So I dunno, I bet more and more people are bringing their own, which is what the indys are trying to stop.

 

Some interesting points. In due time, it will be learned that customer loyalty is more important than immediate profit. However, quality work and location are also important, especially when dealing with older and rarer cars. As always, a little research goes a long way. I was fortunate and found another shop a few miles away, so a look around doesn't hurt.