Rotary Gods, please lend me your insight. I have searched plenty and have yielded no positive results. All the grounds have been cleaned and re done via Aaron Cake's methods and a majority of sensors tested. I also have no cats and a RB presilencer.

Car: S4 NA

The situation:
Two days ago the car ran fine. (slight hesitation at 3800 rpm, been like that for awhile)

Decided to seafoam the gas tank and run through a vaccum line. Car ran fine despite smoking like it obviously should after seafoaming.

Drove the car yesterday and it violently bogged down until you lower the rpms. Get home and take out the spark plugs to find they are covered in carbon.

Clean the carbon off, reset the tps, took it for a spin and it ran perfect! No hesitation at all!

Drove the car to work this morning and it starts bogging down and backfiring again.

Install new plugs. No results

Decide to run water through a vac line. No results

I am at such a loss here. I know it is getting fuel (at least I think) due to the backfires. It also starts up just fine and idles perfectly. Any help greatly appreciated!

 

Sounds like me and you are in the same boat I've tried everything you have but the grounds........

 

I forgot to add:

The car drives fine on 1/4 throttle and cruising. If any more is applied, the backfiring and bogging begin. I thought of injectors; but why would the run like crap, work like a charm after changing plugs, then not work again?

 

dead spot in TPS sweep??

did you resolder the ground loom crimp on the ecu wiring just out from the ecu plug?? if not dont pass go

 

I would say suspect TPS too, next time it does that try unplugging and go for a quick spin to see if it still happens.