jahquan3

I had the check engine light come on about a month and a half ago with stuttered acceleration. I took it to the shop and it was diagnosed as misfiring so I had both ignition coils replaced, both air filters, and 8 plugs.
About a week ago CEL came on with no stuttered acceleration then went off a day or so later right before I was going to take it to the shop again. Yesterday on way to work though it came back on and the stuttered acceleration came back again. So I was low on gas and just decided to let it run almost empty thinking it was a fuel injection or bad fuel issue (I get Super but I go to whatever station is closes type of thing). As soon as low fuel sign comes on CEL goes off and car ran like normal. I went to a chain station (Gulf) and bought the fuel injection cleaner and filled up with Super. On the ride home from there it drove like a champ.
Long story short on way to work today CEL comes back on and stuttered acceleration again. Just went down for a break and took it for a quick spin. CEL light is on still but now it's driving normally.

Weirdest thing ever, either way made an appointment to drop it off in the morning. I wonder what it is this time. I'll keep anyone whose interested in the loop.

Airmousam

Good luck, keep us posted!

BenzV12

I hope that CEL won't call for prognostic giveaways of expensive replacements

The G Man

Misfiring can be cause many things such as coil, plugs or leaky injector. Are you using top tier 91 octane gas? Water in the gas tank can also cause what you are describing. I would stop using those generic gas stations.

jahquan3

I just get the highest at whatever Gas Station I'm at. Usually it's 93 I believe, but I think I might start going to chains only and no more mom and pop type gas stations.

jahquan3

Another question are there other coils other than the two ignition coils I've already had replaced? Also my bill last time said 8 Plugs changed but doesn't my model have 16? I'm at 100k already so I would assume they should've swapped out all 16 if that is the case by now. Other than these questions it leaves only the fuel injector as the culprit.

KEY08

No you have 8 plugs. My old E500 actually was a 16 plug motor. Those are no longer.
You do, however have a coil pack for each plug. I think I asked you last time this came up and you said you had 2 coils replaced. So, you must still have 6 coils that are original and perhaps one or more of them has gone bad on you.

jahquan3

Ah yes, I remember you asking that. Wow..I didn't know that it had that many coils. I thought there were only two. Wel..let's hope I don't need the remaining balance of those replaced. Good information just in case I need to know what I'm looking at. Thx

KEY08

Yeah, a bad coil will set off the CEL for sure. They are usually only replaced if bad, because they are not cheap like spark plugs (not that they are cheap either).

Arrie

When they replaced the two coils how did they know which ones to replace? You have a coil for each spark plug and it would be good to run a scan to see which ones are misfiring if this is the case.

The G Man

I usually use Shell 93 octane on the recommendation of one of my friend which is an Audi mechanic. Another cheap solution is to throw in a bottle of dry gas and Techron, not in the same tank of gas.

Rocman8

post up what cylinders were misfiring previously and what cylinders are misfiring now. also which coils were replaced.

jahquan3

Dropped it off yesterday at 8am and didn't get a call back on diagnosis until almost 6 at night. I'm going back over this morning to get a printout. I was headed to an event in a car of people and had a hard time making out everything he was saying. To sum up what I did hear was that I need a sensor and another ignition coil replaced. Also there was another part I needed that one I'm fuzzy on. He said two of the parts have to come from dealer (MB) and would take 2-3 days to come in. He said MB would need full deposit on those parts and he'd have to physically go over to the dealer to deposit money which he was fine with doing. Total damage with labor would be $1,260 . Once I get print out today I'll report back. I'm assuming they have coils so it must be the sensor and other part they have to order. I'll see if I can order them on my own if it's doable and cheaper if at all possible. Otherwise I'll just have to eat the cost as is.

jahquan3

Good question since my bill didn't specify which one and I was under impression that there were only two. I'll make sure to ask today.

jahquan3

Thx for the insight I'll make sure to gather this information today and report back.

jahquan3

Just left the shop and this is the outcome. Misfire on cylinder 1 this time they didn't have record of which before. Coil they have these items below they'll order.

Canister purge Valve RWD Part# 000 470 55 93

Evaporation Control Canister RWD Part# 211 470 08 59

Pressure Relief Value All applicable Models Part# 000 470 55 93

I don't know how two items have same part # so I assume that's a typo on this printout. I'm gonna have to call them to confirm that.

Rocman8

So it's a bunch of guessing. Take it to a real shop. They are replacing evap components for a cyl 1 misfire? And they don't even know what/where they replaced the last visit? Wow.

KEY08

Canister is full? How bad was your car misfiring? Is this an MB Indy? Sounds awful high for this work to me. Hope it all works out.

The G Man

Deleted

Arrie

Do you have the car back? If so, you can troubleshoot this issue very easily. The misfire as a problem code should not have anything to do with the parts you listed. If it did the misfire would affect all cylinders and not just the no. 1.


Why is that costs so high if the coil is not even included anyway?


For troubleshooting you can take the no. 1 cylinder coil and swap it with another one. If the misfire changes to the cylinder where the "bad" coil now is you know it is a coil issue. This is what I would do before spending a penny for it.


Someone else here can probably tell which one is the cylinder 1. I think it is the first one from the front end of the engine but left or right side I don't know.


The coil change is a very easy job. They are fastened with two screws and to access them you just take the plastic engine cover / air box off the engine and everything is right there for you. Extremely easy job!

jahquan3

The misfire isn't bad at all compared to previous time. It's suddle and not consistent. This shop is STS which recently in the past month was taken over by Mavis in my location.

jahquan3

Yes I have car back. Still deciding on if I'll get second opinion get parts or just let them fix it. Leaning towards the latter unless I can find a close enough shop with hours that work. I got some time off coming so I maybe able to shop around a little more then normal.
For just the parts above it's 800 with no tax included in that estimate. The ignition coil is 100. So the balance would be labor and taxes.

jahquan3

I might be forced to go to my MB Indy I've used before. However they're always a week or two booked and not as prompt as I would like as far as completing service as fast as STS. Also they're closed on Sunday which knocks one of my two days that I can pick up or drop off the car. They do have good prices probably as cheap as STS

The G Man

Please educate me, which canister fills up if the engine misfires? Thank You.

jonUF02

So are you under warranty?

My experience with dealer mechanics is that they hook up the computer, charge you $150, and if they computer does not tell them anything, they start telling you to throw random parts at it with no guarantee of repair rather than going through any logical troubleshooting.

I had such a problem on my CLK430. Rouch idle with no error codes whatsoever. After their "diagnosis" they told me to replace the entire exhaust system, which includes the cats and O2 sensors, at a quote of over $3000. In the end, I fixed the problem myself by disassembling the intake manifold and EGR valve and cleaning everything really well. It had nothing to do with the exhaust, and I spend quite a bit of time analyzing the O2 sensor data which all showed completely normal.