ive done a ton of searching and there are tons of people out there with the same problem my tt has and i cant find a deffinate answer of what seems to be the cause of this

just started doing this since it got cold out around (32degrees)
still did it when it was 58 degrees out???

no cel !!!!! wtf?
backfiring misfiring stalling on start up when cold
after first start of the day it startsfine unless it sits for about 3 hours
once in a while it starts just fine??? even when extremely cold(10 degrees)
runs sluggish all the time
bad gas mileage all the time ---> around 15mpg
have to hold down on gas to get it started
changed coolant temp sensor(cts) and mass air sensor(maf) ---> nothing waste of 250$
---> cleaning pugs help for the first couple starts but all end up black and look moist & smells like gas
normal boost/vac readings
used seafoam for gas tank and octane booster---> didnt help
new air filter ---> no help
no apparent leaks in the intake or vac
replace dv last year

wtf could be causing all of this??? anypeople find a solution?
hit me up with some input on the subject

so far ive heard that possible causes are:

bad / stuck open fuel injector ----> would throw the cel
bad o2 sensors ----> would throw the cel
maf ----> tried that
cts ----> tried that
blown/bad head gasket ----> should be tons of exhaust or foamy or white **** in oil ---> nothing
spark plugs/wires/coil packs -----> would run shitty all the time and should have oneor twofouled plugs at a time -->not all of them
water in gas tank or lines ------> already tried seafoam / other fuel system treatment products ---> nothing
bad gas -----> tried mixing octane booster---> i have same results from any gas station i go to i run 93 octane always
vac/boost or intake leak ---> normal readings on guage and checked intake for leaks (didnt pressure test though)
fuel pressure regulator -----> cleaned ---> nothing
throttle body -----> cleaned around plate ---> nothing

 

If you have a VAG COM, go to the OBD data and watch the CTS sensor and see if it goes crazy like -50 when cranking. If you don't see any problems there get the engine to operating temp and go back to the CTS reading from time to time and see if it wacks out.
After that i want you to log the O2 sensors and data block 32 (fuel trim) and post it here.
Then i want to see the g/s the MAF sensor is reading (at operating temp)