amdreamer1

I have a 2002 Audi TT quattro that has cylinder 4 misfire-code(P0304)
I have changed all 4 spark plugs, to NGK Audi recommended. And all 4 coil packs. Erased the codes. And the problems still exists. What is strange is that, when I start up the engine in the morning, or when the engine has cooled, it does the gurgling/tractor type sound and if you drive it, all the power is gone. Then Check engine starts flashing.... And when the engine has warmed up, then it runs perfect! I also have changed water pump/timing belt couple months back. Anyone had the same problem? if so, how did u fix the problem? and if not, what are your ideas on what the problem could be??? HELP PLEASE!

BruttBam

i had the exact same issue. Changed coil pack,plugs but soon and boost kicked in it would blow the turbo hose off when it backfired.
It took 2 months of research and no luck and then I finally found it.. the tiny vacuum hose that goes from the right hand side of injectors to the left and into the manifold above the alternator had broken off.. I replaced it with a new one today and have never had so much power and no more backfiring. My mechanic was useless . It may help you hopefully.. all the best .

daczone

I had bad coils right out of the box. I then upgraded the newer style, had to do the adapters, but no problems ever since.