I have a 07 MCS, at different times I have been noticing when I go to pull out in traffic or to pass someone by jumping on it my MCS wants to bog-out or as I would say “fall on its face” I also get this sound coming from the engine like the timing is retarded or an electrical spark crackling sound. Hard to explain the sound in words and this don’t happen every time the bog occurs. I due notice it more when I first take off from work or first thing in the morning but again it has happen straight up in the afternoon. I would think if the timing was off this would occur all the time not at random times.

What are your thought and any advice what could be causing this?

Thanks.....Keven

 

HPFP perhaps?

 

Carbon buildup perhaps?

 

I did the seafoam cleaning through the vacuum hose over the weekend, seems to be running better just waiting to see long term. Still not sure if that will resolve the problem but first steps first.

Still open to hear everyone thoughts.

 

I have this issue too, I am about to push the dealer for HPFP.. I have done all the cleanings, new plugs, all sorts of random things.. still there so I am assuming thats the problem.

 

Let us know what they say, it will be a couple of weeks before I can take mine in to have looked at.

 

I hope it works out for you. You are bringing a pretty modded car to the dealer. Sometimes they can be a little uncooperative. My dealer has pretty much disowned the car already.

 

I had the same issue with mine... SeaFoam helped for a few weeks, but then it came back and got worse. First it just did it when I'd try to pass on the highway in 6th gear, then it started acting up in lower gears. I tried changing my sparkplugs and it still had the issue. I sent her in for warranty work for a bad timing chain and have had NO issues since. It's been 6000 miles since the repair work was done and she runs like a dream!

If it sounds like a diesel upon start up, I would recomend you have the dealer check if the timing chain is out of spec.

 

First things first. Check the plugs. You can tell a lot by looking. Make sure they are gapped correctly. Next make sure the contacts on the coil are clean and good. Wires need to be changed sooner or later. They do last longer these days. At one time spraying with water would bring out shorts (If water made the engine stutter, it was time to buy new ones) I'm not sure that works anymore. Airfilter next, clogged will show up at higher RPMs.
In other words, a basic tune up. Then move on to more $$$ parts.

Not sure it will help anyone here, but it isn't a bad way to go about things.

 

I just went to the dealer today for unrelated issues. I talked to the actual tech working on my car about some things as I wanted him to check my injectors for build-up. He said you would know when they are bad (have build-up) if your car does exactly as you described.

-z

 

thursday I go in for a new HPFP

 

HPFP was replaced to under warranty even with all my mods.

 

Great to hear; what was the mileage on the vehicle at the time of replacement?

- Erik

 

Mine was 65k miles, i started noticing issues at around 56k miles - i know bad.

But when i noticed it i went on a maintenance spree cause i thought maybe it was the timing chain or plugs or something else before i realized it was fuel related.

Mine was very intermittent