mpg dropping like a rock

[phillypino215]

when i first got the car a little over a year ago, id average roughly 22-23 mpg. currently im down to almost 17-18 mpg. nothing has really changed since i got the car. commute to work is still the same.

http://www.fuelly.com/car/audi/a4_qu...pino215/358413

as ashamed as i am to admit this. took this car down the track for my first time ever and consistently hit 15's, pretty sure thats not good with a car with a stage 2 tune even as a noob.

why's my car broken?! any hints at what i should be looking at?

[Dub_prime]

Do a general tune up, plugs and such, then check for carbon deposits.

[adamazing]

First thought is carbon buildup, maybe?

[blbroo]

I agree with Dub and Adam.

[phillypino215]

just replaced plugs, coilpacks and oil change. ill check for carbon buildup.

[Dub_prime]

just replaced plugs, coilpacks and oil change. ill check for carbon buildup.

Are you getting misfires or throwing any codes?

[phillypino215]

i threw codes for misfires hence changing out coilpacks and plugs, no more codes since switching them out but still idling pretty rough from a cold start.

[Dub_prime]

i threw codes for misfires hence changing out coilpacks and plugs, no more codes since switching them out but still idling pretty rough from a cold start.

That's a pretty good indication of build up, any oil consumption?

[phillypino215]

surprisingly no, oil consumption is zero.

[Rollin Thunder]

Def agree with the above on carbon buildup.

[OzeyeruZ]

Remove the 2 large packs of bottled water and two folding chairs from your trunk you would have been hitting 14's! Lol. All joking aside, maybe time for a carbon cleaning Then lets go back to the track!

Oz

[Liquid Smoke]

sounds too simple, but if you hadn't already, also check your tire psi. sometimes if one of them is off or they are slightly lower than the usual it will have a decent effect on mpg.

[dracolnyte]

i put in a bottle of those engine restorer like rislone with the intention of trying to fix oil consumption but all it did was improve my mpg lol

[Yavstr]

I had a problem with my 09 where the MPG was going down and oil consumption was very high.
I changed the plugs had an oil change with no luck.
Checked for codes and clean.

To make matters worse at various times the car would have a violent jerking while accelerating. I checked the coil packs and nothing.

Finally took the car to the dealer and after a full week of being there they finally got a misfire to register on cyl. one.
So they checked the coil packs and the plugs and it wasn't either of those. They then checked the injectors for leaks (nothing there).
They moved on to trying to check for metal in the oil and ran into some issues. The other dealer in my area decided to use lock-tight to put my oil pan back on and even put the screws in sideways and stripped them. Oh the joys. Long story short, all of the injectors were shot and there was a crack in the manifold.

I actually became quite fond of a 2013 A4 on the lot and traded mine in on that.

Good luck with you're problem.

[phillypino215]

sounds too simple, but if you hadn't already, also check your tire psi. sometimes if one of them is off or they are slightly lower than the usual it will have a decent effect on mpg.

thanks for that, but im pretty anal with my psi. so atleast thats one thing checked off...

- - - Updated - - -

Remove the 2 large packs of bottled water and two folding chairs from your trunk you would have been hitting 14's! Lol. All joking aside, maybe time for a carbon cleaning Then lets go back to the track!

Oz

i may have to keep them in there just to have an excuse!

[mecg]

I would check for vacuum leaks. Your symptoms are classic for unmetered air getting into the engine.