AMGFTW

Looking for some help from those that have experienced this issue. My 2009 with 29k miles will sometimes have a slight "tug" effect at part throttle. This seems to occur around 2500-4000rpms and is not a constant issue. It will do it while accelerating as well as on the highway when throttle input is between 30-50%.

Yesterday I was accelerating from a stop at about 50% throttle and the car began jerking even harder than usual in 3rd gear. I have yet to throw a CEL so making an accurate diagnosis has been a pain to say the least. I prefer to fix the issue myself instead of taking it to my MB dealership.

Current mods:
MHP V3 CDT
MHP Long Tubes and Mids
K&N’s with Charcoal removed

This problem has only become present for around the last 500 miles or so. I have had the K&N’s with the charcoal filters removed for a while now and never had this issue.

So far I have checked or done the following:
Removed the entire intake system minus the IM and checked for leaks – None Found
Removed, inspected and cleaned the MAF sensors – No issue apparent
Removed, inspected and cleaned the upstream O2’s – No issue apparent
Reset ECU – Didn’t remedy the issue
Checked for vacuum leaks including gas cap – No leaks
Fuel is good – Shell 93 octane

At this point I am thinking I either have a leaking IM gasket (ordered a set today) or my spark plugs are bad (highly doubtful) any help would be appreciated because this is driving me insane.

Kent

xtyper

Doesn't sound like a problem that can be easily diagnosed without the help of a dealer. I'm surprised with the obvious issues you're experiencing that a CEL has not been triggered. Assuming your dealer is mod friendly and won't axe your warranty upon seeing the MHP setup, I would let them take a look at it asap.

Good luck and keep us posted.

bluejae

i know this is off-topic but in your sig, are you on skinnies? is that the set up you had when you got the time you have in your sig?

AMGFTW

I know right? I'm going to go ahead and pull the intake manifold and replace the gaskets since they are cheap. After that I'll try the stock paper filters to see if that fixes the issue.

Worse case scenario I'll hit up the dealer. Problem is my cool SA is out till next week on vacation.

AMGFTW

Yep all stock minus the wheels and MHP Tune. At my local sh*thole track here in Ohio this summer.

GHAZAN

sounds normal to me

AMGFTW

I bet

So here is a quick update. I finally got a check engine light today on the way to work. So I called a friend of mine that is a MB tech so he could pull a quick log with the STAR. This is what it says:

Code 1352 - Mass air flow sensor 1 has a malfunction
Code 3695 - The measured air mass of component 'B2/6 (Left hot film mass air flow sensor)' is implausible compared to the position of the throttle valves

So at this point I am gonna go with cold air + K&N's + deleted charcoal is just a little too much air for the mafs. I am going to try the stock filters this weekend and see if it makes a difference.

xtyper

Sounds more like a faulty sensor than the intake tract. I'm betting your filters & charcoal deletes are fine, but that you will have to replace the sensor.

AMGFTW

Yeah the more I think about it the more that seems plausible. My buddy is a tech and does not work on the cars other than basic maintenance so we asked another mechanic. His response was "The maf sensors rarely go bad. It has to do with the headers and it sounds like you have an exhaust leak."

I found that a little funny to say the least. They said to have the MAF replaced under warranty the shop foreman would have to approve and they told me he wouldn't because of the headers. LOL

My friend who is a SA at our other local MB is back Monday. So if all else fails I will be making a trip to see him and have the MAF sensor replaced then.

GMW

I experienced a similar thing like your issue (though my car only has the ECU tune) and it's now solved and hope this works for you too.

Did you check the spark plugs and engine air filters. It the spark plugs have some buildup on them, it could cause that and/or if the air filters have a lot of dust, same effect.

Just had mine done and the car is running smoother and feeling stronger throughout the rev range. The slight tug/hesitation when accelerating between 2,000rpm and 3,000rpm is gone.

AMGFTW

Haven't checked the spark plugs. However I put the stock paper filters in on Friday and hit up my local track to take advantage of the cool temps. The filters seemed to remedy the issue from what I could tell. Ended up making about 21 passed before getting booted for no cage. I am still going to take the car to the other local dealership to see if I can get the MAF warrantied.

Thanks for the help

xtyper

You ran an 11.3@126?!?!?! Wow!!! Please post a thread with details please, as that is a great time and third best N/A trap speed!

AMGFTW

Thanks man! I know Andy was excited when I called him from the track Friday haha

My goal was low 11's at mid 120's. I can't believe how these cars keep getting faster and faster the more passes you make. I ended up making 21 passes all within a 2 hour time span and the car just kept getting quicker. Every couple of passes the car would pick up a little more.

I knew this car was strong when I bought it from Jim (RaleighC63) he went 11.6@120 on just the tune at MIR.

I really wish our track prep was up to par with MIR lol. I would gladly trade that MPH for a better ET. The first 300' of track was slick as could be which is indicitive of the higher trap speed. I never was able to get the car to 60' under a 1.7.

I am planning on taking out some weight and hitting up an MIR rental this winter with Andy and the crew. Hopefully I can wiggle my way towards that 11.0 mark

SonnyakaPig

Awesome time/mph. These cars continue to impress with the setup you have.

xtyper

No doubt, with some slightly better conditions, moderate weight removal, your car is capable of 10's. Dodger better look out. Congrats again!

AMGFTW

Thanks brother. I don't think Dodger has much to worry about lol I would just be tickled sh*tless to get into the 10's period.

Merc63

Have you had your A/F checked? How do the spark plus look?

Did you just recently install K&N or wash/oil them?

The oil from the filters can get on the MAF and cause it to fail according to my MB tech buddy. Hes seen it happen before.

Even Money

Speaking of spark plugs, I had the brisk silver racing installed a few months back, one step colder. Haven't been back to the dyno or strip, unfortunately due to the weather up here. However, I did notice a slight MPG increase.

That's an awesome time/mph, btw. You're right about multiple passes. Track rentals are what's needed to get those back to back runs..

Leon Bacon

I had similar problems, chased it with the tuner for weeks until engine decided to almost stop with flashing ECU. Turned out to be failed exhaust cam solenoid, stuck in one position. What I don't know is if the preceding issues were the solenoid failing in a graceful manner. But since replaced haven't had an issue since.

AMGFTW

Thanks again for all of the responses and help.

I took the car to my "friendly" dealer and we ran a few more test. It looks as if my passenger side maf sensor is giving incorrect readings. So they went ahead and ordered me a new one. I'll update once its installed.

Martziniuk

Don’t you just hate it when people say they’ll update then don’t 😫

roadkillrob

most of us got over it in the past 9 years, bumping useless 9 year old posts also something I hate.

Martziniuk

A 9 year post that could potentially help me and that the OP may see and reply to, or even someone else may chime in with a similar issue.
So yeah not useless to me

CodySaurus

09' 90k miles. I also popped into this thread looking for insight to the hesitation in the 2k-3k rpm range. Had a CEL for MAFs, cleaned them and cleared code and it hasnt returned. But hesitation was still there, and it was cheaper to buy new injectors than clean them, so replaced injectors. Getting on the highway yesterday, it had the worst hesitation in that range than ever before - the wife in the passenger seat could even tell. It was as if I was chopping the throttle. No other CELs are popping up though. Send help.

Jasonoff

Crack/corrosion in the IM or an improper seal at the Y pipe.

/thread