KYNZ

so recently i bought a 98 A8 and driving on the highway the other night i got the dreaded CEL...i ran the codes and i threw P0301. I also found that in the stored codes were P0300, P0306, P0307 and P0442. I read that the 0300 codes relate to cylinder misfires and i was curious as to what might cause this. I was thinking plugs or coilpaks but i wanted to know what you all thought about this problem. The 0442 relates to a EVAP small leak supposedly but i dont even know where to begin with that one. HELP...i have to get it inspected this friday.

Jkay

Small EVAP leak is normally a bad gas cap. It gets pressurized, and needs to have a good seal. There is a Recall for the gas tank inspection port seal as well, but you would SMELL GAS if this was bad, since it is under the carpet in the trunk.

As for the misfires, verify a coil pak problem by trading the suspected bad one for a suspected good one. The code will change to a new cylinder.

KYNZ

out of curiousity, since i have thrown multiple codes for MULTIPLE cylinders and then the CEL goes off after a day or so, could this possibly be plugs rather than CPaks? i was planning on following Paul W's advice on audipages and put in Bosch Platinum +4s this weekend. I will report back with results.

tozoM8

It is going to be something else. Coil packs or spark plugs don't go bad all at the same time.

Jkay

Couldn't hurt to check. Those codes could have been building for a year .. who knows?

tonypai

You should run measuring block tests for the engine speed sensor rotor.

Are you getting a misfire for 1-4-6-7 or 2-3-5-8? then you should check the ignition coil power output. I had this error code and it turned out to be water in the connectors.

KYNZ

yeah, the only one that I THREW was p0301, the rest were stored in the STORED CODES column. I was gonna try and do plugs this weekend (if she dosent need anything for inspection tomorrow) and see if that helps. It seems to only throw the code when im on the highway at 60-80mph at low rpm. around town it drives fine. I also had the weird vibration on the highway in the pedal right around 2k so thoughts there? I felt that around the same time as the light began to blink and then stayed on.