I have a 03 audi quattro 1.8t

and it feels underpowered and idles rough, but at all other rpms it's fine. no problems minus the being underpowered part. i'm talking 0-60 in about a minute. Flooring it at 70 and not going. I don't think it's the turbo is out because i can hear it spool down when i shut the car off.

 

how many miles? and have you done mantinence it could be one big thing or just a bunch of little things oil change trans oil change air filter mabye fuel filter mabye even try seafoaming the car i just did mine put some in the gas tank and into the intake it actually worked lol post more info.

 

Fixed what i hope to be the whole problem if not. 90% of it. MAF sensor was bad. unplugged it no more lights. but the code still throws tps sensor, and maf. so hopefully those two will clear it up. I'm also changing the oil and everything tomorrow as well. Just bought the car.

 

ya ok gotcha im kinda going through the same thing with mine right now had it for 3 months had to fix a bad crank sensor but just doing some mantinence rit now. you should be fine.

 

How does it drive with the MAF removed? It should be much smoother, but its only running VIA the O2 sensors.

 

replaced maf sensor. and found a crack in a vaccum hose elbow. fixed those two. still idling rough. not as bad. but still idling rough.

The codes i'm throwing are.

Random misfire

Cylinder 1 misfire

Cylinder 2 misfire

Changed spark plugs, and oil, and valve cover gasket today. Spark plugs were kinda white on the tip. Making me think it was running lean. It threw the code when i was doing about 45 accelerating hard. So i'm venturing to guess fuel system related.

Fuel pump or filter? or both? maybe fuel pressure regulator?

Also where is the check valve in the fuel line?

 

After more investigation. I'm still going with vacuum leak.... lack of fuel should only cause running lean. shouldn't cause idle issue.......someone want to clear that up for me?

 

Check valve in the fuel line is at the firewall end of the rail. Have your coilpacks been replaced? Has the fuel filter been replaced?

 

is your car still running rough idle? most of the time when its coil packs the mil will start to flash. have u gotten a diagram of the vac lines and gone through each of them to make sure their isnt any visible cracks or anything.

 

well after doing the handy dandy vacuum boost test technique on a4mods.com i found that there were no leaks in the vacuum system. but in order to do this properly your supposed to remove the pcv valve out of the equation. therefore with it being the last vacuum issue. i cleaned it off and attempted to blow through both holes. and i was successful. thus meaning. bad pcv valve. started the car with it pinched off. ran just fine..... talk about a PITA.

I'm going to return the coil packs i bought because i thought that might also be the problem. Well my brother kept aruging with me that it was for hours and hours.

Problem solved. Going to do the vacuum /check valve removal/simplification thing on audizine.