Random misfire
 

I am getting the P0300 and P0306 code. Cylinder 6 misfire and multiple cylinder misfire. This happened once right after I changed the plugs and I just messed with the wires/hoses/lines and it went away. This time it didn't go away for a little while. Have any of you run across this and what as your fix?

Check the gap to be sure it's correct, be sure the plug isn't loose in the head, look for bluing on the coilpack to be sure it isn't arcing, etc. there's a smaller chance it could be the injector too - a bottle of Seafoam in the gas tank might help in that regard.

Wash and clean the hi tension cables, then spray the outside with silicone lube. Use di-lectric grease on the spark plug and coilpack ends this will help preserve the cables and might help with arcing if they are't beyond redemption. If the hi-tension cables are old I'd replace them and spray the new ones with silicone lube and use di-lectric grease at the connections. Don't use silicone lube inside the connections because it is not a conductor and could affect the commection.(highly unlikely though), Simply put silicone seals and preserves rubber and many other materials too ( like winter boots etc.)

This is a common symptom of.........





...... you not connecting the coils properly to the harness... go back and make sure they are all in properly, if they are then your harness is frayed and shorting in a few places, normally where they separate to the left bank and right bank.

Hey guys, I PM'd ImTheDevil with this but thought I'd throw my troubles out there. I've got an '04 A4 Avant Quattro 3.0L.

A couple months ago I took it into a dealer for a 98,000 mile check up, they cleared my CEL and replaced all IGNITION COILS. When I left, the car was running erratically. RPMs fluctuating up to almost 2k while idling. CEL starting blinking, took it back it and let the dealer know they jacked my car up. They had it in their garage for 5 weeks "diagnosing the issue." They "said" they swapped coils, spark plugs sensors, etc. and finally said it was my cam chain tensioner and quoted me $5,000 to fix and can't do any more free work for me. So I just continued to drive it thinking I would just drive it into the ground, not worth the fix. But now I want to fix it myself, I'm a mechanical engineer for goodness sake.

My CEL codes are:
P0345 CAMSHAFT POSITION SENSOR
P0300 MULTIPLE CYLINDER MISFIRE
P0304-P0306 CYLINDER 4-6 MISFIRE

So everything on Bank 2, driver's side. The car will sometimes run just fine, the CEL will go away only to come back 2 days later and add some roughness/vibration to its operation, the erratic RPM fluctuation was fixed by an oil flush.

I've only just realized now that a 3.0L engine doesn't have a cam chain tensioner which seems to be an issue on older 1.8T cars, the 3.0L AVK has a timing belt tensioner/adjuster instead. I figure it can't be the timing belt tensioner/adjuster because it services both engine banks and runs on the slack side of the timing loop and this problems is localized on bank 2. Is that good reasoning?

Now I don't trust anything the dealership told me they did and am going to swap cam position sensors myself this afternoon and see if the codes jump to the other bank. I've noticed these same codes and problems on 1.8T forums and most diagnose the issue as the cam chain tensioner, which the 3.0L doesn't have.

A week ago I started getting a high pitched humming noise from steering at low speeds. I checked the steering hydraulics mineral oil level and it was fine. I'm not sure if this problem is related at all, I doubt it is.

There you have it, sorry for the long rant, but it has a long history.

Any ideas?

Thanks in advance,

Rhys

Was your car running ok befor the dealer did the work?? First complain to the main audi rep in your area and try to get it fixed properly from another dealer thats my recomendation. Baring that check for vacuum leaks and loose connections, sounds like something not connected right in bank2!!

have u checked your maf? Try unpluggin it when the car is sputtering. though i think it might be ur coilpack harness. HAve u inspected it for exposed wires. Though normally when the wires are crap it will throw a fuse!

Barewake2, I saw your PM and then saw it posted here so I'll chime in here. If there is no CCT in your engine, then you have a gripe for Audi of America since the dealer blatantly blew you off and gave you a complete bullshit price on parts that don't exist in your car. To me it sounds like your bank 2 cam jumped a tooth on the timing belt. It'd explain all your issues if the cam sensor isn't bad. Try your sensor swap and if the symptoms don't change to bank 1, look at timing (and do it soon). All engine vacuum is common to the whole engine, as is input/effects from the MAF, so a bad MAF or a vacuum leak wouldn't affect only one side of the engine. Your faults are confined to one side, so if its not the sensor, a belt jump makes sense.

Hey guys, I've swapped my cam position sensors so I'll wait and see if the CEL light comes back on with misfire codes from Bank 1. I thought about the possibility of a belt jump, but isn't this emgine and interference engine? Would a belt jump cause the engine to run super bad and practically self destruct?

It is, but it won't hit by jumping one tooth. Jumping two teeth would run badly and three would mulch the valvetrain.