Problem with my car, I'll go crazy VAGCOM FAULTS

[SPORTUNING]

The car is an RS6 Avant Quattro for 4.2 Biturbo with exhaust, turbos hybridized, filters and ECU MTM 570 - 580cv.

Well the fact is that a month ago I had problems with it and finally got it repaired, beginning to put him on Vagcom I got these errors:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
16688 - Cylinder 3: Misfire Detected
P0303 - 001 - Upper Limit Exceeded
16692 - Cylinder 6: Misfire Detected
P0306 - 001 - Upper Limit Exceeded - Intermittent
16487 - Mass Air Flow Sensor (G70): Signal too High
P0103 - 001 - Upper Limit Exceeded - Intermittent
17482 - Mass Air Flow Sensor 2 (G246): Signal too High
P1074 - 001 - Upper Limit Exceeded - Intermittent
17963 - Charge Pressure: Maximum Limit Exceeded
P1555 - 001 - Upper Limit Exceeded - Intermittent
Readiness: 0110 1001

I did this .... chooses to look coils, MAFS, and the sleeves of the Turbo IC, what was my surprise that when removing the coil No. 3 spark plug was loose, so review them all, and all loose.
Change the 8 spark plugs, as they had not NGK put brand BERU, look at the MAFS and No. 2 had a broken wire, fix it, look at the sleeves and one of them badly fucked with the flange to point out, you change the flange and got to the site. With all this the car was like a rocket, no problem yet when I gave the volatility marked the two MAFS, but going well.

A few days ago began to backfire again (fake explosions at full throttle) and only gave me both error and missfire MAFS, this time in cylinders 4 and 8, so choose to change the 2 MAFS with the hope of ending with the problem ... but has not been so the car is better but still fails when accelerating hard ... Sometimes it is like without blowing two turbos and I'm still checking these errors:

16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
16688 - Cylinder 4: Misfire Detected
P0304 - 001 - Upper Limit Exceeded
16692 - Cylinder 8: Misfire Detected
P0308 - 001 - Upper Limit Exceeded - Intermittent
16487 - Mass Air Flow Sensor (G70): Signal too High
P0103 - 001 - Upper Limit Exceeded - Intermittent
17482 - Mass Air Flow Sensor 2 (G246): Signal too High
P1074 - 001 - Upper Limit Exceeded - Intermittent
17963 - Charge Pressure: Maximum Limit Exceeded
P1555 - 001 - Upper Limit Exceeded - Intermittent

I have deleted everything, I checked the hoses were not loose the 2 MAFS were ok, and I gave a lap, after lap I check this:

5 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 001 - Upper Limit Exceeded
16688 - Cylinder 4: Misfire Detected
P0304 - 001 - Upper Limit Exceeded
16487 - Mass Air Flow Sensor (G70): Signal too High
P0103 - 001 - Upper Limit Exceeded - Intermittent
17482 - Mass Air Flow Sensor 2 (G246): Signal too High
P1074 - 001 - Upper Limit Exceeded - Intermittent
17963 - Charge Pressure: Maximum Limit Exceeded
P1555 - 001 - Upper Limit Exceeded - Intermittent
Readiness: 0110 1001

I'm going to go crazy, I'll look coils and spark plugs, BERU spark plugs do not give me confidence, I will put the NGK.
I also thought that the explosions are false for the fuel filter, could be relevant for the gas pump?
The MAFS could give me some tube failure on the N75, or the N75 that is broken or because the ECU TUNED not well, I thought about going and put a REVO stage2

once again sorry for my English...

[ttboost]

Overboosting and going into limp mode? Try a new N75?

[hahnmgh63]

To start with the MAF "Signal too High" is fairly common for a chipped/modified car. Just means the MAF's are reading their limit (stock limit tolerance). No problem there most likely. If they read "Signal low" that would be a problem. But if you are going to have the air cleaner off you should double check the MAF pipe inlet seals/o-rings as they can wear with age and multiple removals. I lube mine with Silicone grease to keep a good seal and to keep them from ripping when installing or removing the air cleaner.
Your misfires are a problem though as well as your "Upper limit exceeded" although it is intermittent. For the misfires check plugs (OEM is NGK) and most would say on a boosted car to run the gap slightly tighter than stock as the extra boost can quench the spark. Also check the Coils, they should be the 115E and most (at least the Audi tt crowd) swear by the Hitachi manufactured coils. And if all else fails the wiring to the coils should be checked as it gets brittle with age & heat and our cars are getting older.
The upper limit exceeded could be a few things. I would check the N75 valve (probably somewhere around 80 Euro for a new one). Also check the vacuum lines going to the N75 and to the wastegates. This one was intermittent so you may want to fix the misfire problem first then get to this one, could even be a MTM software issure on this one.

[SPORTUNING]

Well, yesterday I went shopping, I buy a N75 valve, a vacuum valve, a relay of the fuel pump, fuel filter, 8 spark plugs NGK PFR7Q, two OEM air filters, I hope that with this and reviewing all the tubes the car works well. Otherwise the next step will be to change coils and electronic switch back. Thank you all.

[ben916]

I might suggest a "red neck reset" - anyone concur?

[JCviggen]

To start with the MAF "Signal too High" is fairly common for a chipped/modified car.

If they are properly remapped then that shouldn't happen.

Anyway check the lines to and from the N75 as well. If those are leaking the wastegates will see insufficient pressure to the actuators and stay closed which leads to serious overboosting. And that's bad, you can basically ruin your engine.