docJHH45

I have a 00 TA (non-ws6) M6, 41k on the clock. I bought it in November, and put less than 100 miles on it over the winter (weather was pretty sh!tty up here this year).

The car was bone stock, and everytime I pulled the clutch in, or revved it over 4k the exhaust note would breakup and give a loud pop (almost like a gunshot). As the car warmed up it would get slightly better, but def still there. I have a 99 A4 TA that I bought brand new (never been modded)... and I expected the new M6 to be much faster. But after putting some miles on it, I have to say the M6 feels slower, which is starting to make me think something is seriously wrong with this bird.

Well this weekend I started some mods: LM1 cb, slp lid, new resin ported MAF housing, and the free RA mod. The exhaust breakup is now 100 worse. I don;t think the mods really made it worse, more that I can now not ignore how bad it the problem really is. My car sounds terrible.

Here are my thoughts of what it could be:

1. bad Cats. I've heard of recalls on the cats, or others having a similar noise due to unburnt exhaust gas igniting in the cats. (My SES light has not come on)

2. Tune up. Maybe bads plugs & wires. I assume they have never been replaced.

3. When doing the MAF housing, I saw that the MAF wires had a pretty bad buildup of dirt an oil on them. I did not clean them, as I'm afraid to damage it. Maybe the its not getting a correct reading and running lean... has anyone tried cleaning their MAF before, what did you use?

4. clogged fuel injectors... not a big fan of the fuel system cleaners and additives, but its worth a try.

I appreciate any suggestions, or comments from anyone else that had a similar experience.

Thanks everyone - Ev

LSxChevelle

iTrader: (4)

You can clean the maf with brake kleen and then let it dry before you use. Change the plugs and wires since its something you may as well do. If there is still a problem check compression. (may as well do this when changing plugs...)

Jason

docJHH45

Thanks! I have all my plugs and wires ready to install... I just dread doing that #8 plug, what a bitch.

I'm gona swap the MAF out of my 99 tonight, while I clean this one... hopefully this is the issue.

How do you check compression?

LSxChevelle

iTrader: (4)

You can just get a leakdown kit at Harbor Freight tools for like $30. Allows you to check leak down, compression, and also load cylinders with air for spring swaps without the valves falling down.

Your local parts store should have a compression gauge setup. The hose has a threaded end that you screw into the spark plug hole. Then have someone crank it over while you watch the gauge. Just unplug the coil packs while you crank it.

Jason

docJHH45

I cleaned my MAF, with BrakeKleen brand MAF cleaner.... no change
Swapped out my MAF from my other TA... no change
ran some STP injector cleaner.... put 50 miles on her, no change

made an appointment with the stealer for thurs morn... I'll keep posting updates for anyone who cares.

If anyone else has any info, it would be greatly appreciated.

docJHH45

I could really use some more help on this guys/gals.

I did the plugs and wires (double checked them for correct gap)... no change

I spent over an hour yesterday reading old posts about this, and didn't come up with anything conclusive.

I dropped it off at the local Pontiac stealer this morning for them to check out the cats. They just called me back and said that its my aftermarket exhaust making the noise, come pay your $89 diag fee and pick up your car. I told them, that the car started making that noise 1000 miles before I put the SLP exhaust on (which was just this weekend). Now they want to charge more diag time to look at it more. WTF???!!!!!

docJHH45

They just called back... now the tech (who says he's been a GM tech for 18 years and is their LS1 specialist) says there is definitely no probably and he can't hear any noises. (This popping noise sounds louder than my Beretta .40 caliber firing, no way anyone with half a brain could miss it).

He said he updated my PCM, and cleaned my MAF (which I told them when I dropped it off, had already been done) and my total cost is $220 something.

I asked him to go on a test drive with me when I got there so I could point it out. He continued to argue it was fine, and said he would be too busy.

Hopefully, I can keep my cool when I go pick it up... because I am not paying anyone over $200 to tell me they have no clue whats wrong with it....

docJHH45

I spent over 3 hours reading old posts today... order some AIR block off plates, hopefully removal of this system will help.