I am a newly Audi owner. I am very proud to say that I own an Audi, but i am having some problems. I bought the car for a winter college car that would be comfortable since I am a tall guy.

On to the car problem. The CEL is on and it also blinks. I have read the codes and keep getting the following codes, P0300,P0301,P0302,P0303. I know that the codes are multiple misfires and on cylinders 1-3. I have replaced spark plugs, coil pack, and also put injection cleaner in. The day I put the injection cleaner in I ran it for about 100 miles and the light stayed off. The following day I had inspection and the light came back on, there for not passing. I am currently in need of any help because it is hard for me to travel back and fourth to college without an inspected car. The car runs amazing and its weird that it has this misfire. When I first turn it on the engine runs around 1100 rpm and then idles down to around 800 rpm then seems a little hesitant and sort of rough but not that bad. Any sort of help would be much appriciated. Thank you!

Please help!!!!

 

Misfires are often the result of leaking vacuum lines...also leaking vacuum lines not unusual on a 1998 used car. In your case the random and cylinder misfires are all on the passenger bank (1,2,3). Not knowing the particular engine/car you're in, perhaps replacing the coils that run cylinders 1, 2, 3 will be necessary or perhaps the coil wires.

Perhaps you put in the wrong spark plugs? Use NGKs specified for your engine.

Find the vacuum leak on the passenger bank of the engine.

Clean the mass airflow sensor with the right cleaner.

Did the previous owner put in one of those damnable oiled fabric air cleaners to try and get more power or for whatever reason? The K&N filters have been known to foul MAF sensors.

Is there a manifold leak on the passenger side?

One technique is to use a smoker to find vacuum leaks...the induction system is mildly pressurized and oil smoke is injected...

Another technique is to use a propane or MAPP gas torch (don't light it!) to wash propane around various components and locations to see if engine speed changes momentarily which would indicate a vacuum leak at that component/location.

Dunno if there's an idle stabilizer valve or idle air conrol valve on this car/engine, you'll have to look it up and if it does, remove it and clean it. The IAC valve is used by the engine control unit to control idle speed..it bypasses the throttle body. I think you have a throttle cable to your throttle body rather than a drive-by-wire, there should be an electric component that controls the idle speed.

 

All your problems are isolated to bank 1. Generally a vac leak will effect both banks, but it is possible to just be on side. Intake gasket vac leak would be on one side. Are the plug wells dry? Leaky valve cover gasket can let oil into the plug wells and cause a misfire. Plug wires maybe, but would be odd to all be on one side.

Since you did the coilpack and plugs your getting down to a possible fuel problem on bank 1 or mechanical problem. If car was overheated badly in the past you could have a headgasket issue or someone messed up a TB job and bank 1 is timed wrong. Leak down or compression test would let you know about headgasket and maybe timing. Cam lock bar and crank pin will let you check timing.