Slight Hesitation / Black Soot
 

2009 Base M6 w/ 14,800 on the clock. Not a daily driver but when I drive it (usually once a week) I don't baby it. Lately when i'm lugging it I've noticed a slight hesistation in it but goes away real quick when it give it a little more throttle. I wasn't 100% sure it was a hesitation but lately I've noticed after putting 200 ish miles on it that my center exhaust pipes are real black with soot. I've never seen them get that dirty that quick before. I have M2W installed that why it's on the center pipes I believe. I poured a container of Seafoam in to the fuel in the last week of Auguest and drove it to the tank was almost empty. I use Exxon Premimum fuel only in the car. Any ideas?

Thanks!

It could be a dirty air filter or MAF sensor, or it could be normal. Do you have the stock or aftermarket air intake system?

If aftermarket and it is an oiled air filter, it can contaminate the sensor.

The center pipes do get "black" with normal driving, if left "open" with the MTW switch.

IF the car is in "good tuning" conditionmeaning no current issues, an aftermarket tune will greatly eliminate the pipe buildup.

These cars naturally run a little rich it seems.

No CAI, OEM Filter, never looked at it to be honest. Stock tune as well. The pipes have never gotten this direty this quickly, only in the last few weeks. Last night I got on it in competition mode and it gave me poof of black carbon out the pipes, it's never done that before either.

Loose spark plug wire? Just a guess.

How often do you lug the motor?.i never let tach below 2grand...........you might need an italian tuneup...........:d

Your motor might have a lot of carbon build up if you lug it all time.seafoam doing it's job..go to shell gas and fill it up with 93 and go run car hard...........

I dont lug it often and everytime I do drive it I do drive it hard at least once to blow it all out. This has started within the last month or so, something has changed, just not sure what it could be.

I also have an '09 but it's an A6 and I get a hesitation too; it's always after I've coasted (say slowing down for a red light that turns green before I stop) and then touch the gas to speed up "normally". The hesitation doesn't last long, but it's there. I've had dealers check it 4 times and an independent shop check it once and they say they can find nothing wrong.

I don't have any more than the normal amount of soot on the tips though, and I don't get smoke when I accelerate hard.

Have you checked it for any codes?

No, I have not, it's not showing any lights nor has it in the past but I will check since I have a scanner which is collecting dust anyway.

Hi Eppie,

Use the dusty code reader! Let us know what codes, if any come up. If you do decide to have it checked out, let me know. I am not technical :( but I can help in other ways. Have a great weekend and hopefully you have her up and running well by next week,

Kelly J.
Chevrolet Customer Care