Rough idle and misfire on cold starts

[jayson161]

Over the last week my car has been misfiring on cold starts and idling around 1200rpm before settling down. Once warm it'll start up smooth every time. I had the coilpacks replaced, open recall from Audi, and also the valve cover gasket. There was some oil found on the coilpack when it was pulled out. The car ran fine for a day or so and went back to the rough idle and misfire. My CEL just popped back on as well. It's throwing codes 300,301,302, and 304.

Does anybody have similar experience and were able to find a solution?

[travrach]

Does it only run bad when cold, and never again the rest of the drive? Are you using any coolant?

[jayson161]

Yeah, it only runs bad after it's been sitting for a couple hours and then it settles down. The coolant level is where it should be and I've been using Audi's G12.

[wolfdog]

Mine does it in cold cold weather. When I replaced the valve cover gasket I had to come back a week+ later to tighten down the bolts again. Made a huge difference. I also seem to find holes in some hoses when that happens or when my car likes to jerk when shifting gears.

[BARRY]

are you getting any check engine lights?

[jayson161]

are you getting any check engine lights?

When it first happened it popped on the CEL with code p300,301,302, and 304. I just swapped my coil packs around and it only came up with p300 this time around.

[markskyline]

You're not losing any coolant? If you are then it could be either a cracked head or bad head gasket. If not then check/clean your MAF.

[frenchyofcp]

Check your spark plugs.

[jayson161]

There is no sign of coolant loss. How can I tell if the MAF is bad?

[jayson161]

Update: There was no issue with a misfire this morning, just retained the slightly higher rpm of about 1200 or so. Only other thing to note is there was a little more oil around the first spark plug than there was yesterday. It has since subsided since the morning though.

[Charles.waite]

Update: There was no issue with a misfire this morning, just retained the slightly higher rpm of about 1200 or so. Only other thing to note is there was a little more oil around the first spark plug than there was yesterday. It has since subsided since the morning though.

The high idle is normal on cold starts in case you didn't know. It should last for around a minute then drop down to ~780. I would check your spark plugs are gapped properly, torques properly and aren't worn out. If there's oil around the plugs you should replace the valve cover gasket and check out the pcv and probably replace that as well. I can almost guarantee you that the rear pcv breather (if you're my 2004 and above) will snap and you'll have to replace it. The OEM part is retardedly pricey for what it is. Get the 034 silicon breather kit and be done messing with the pcv forever.

/my2¢

[jayson161]

That's actually a huge help. I didn't even think of the idle as being normal, my brain was in "oh fuck there's more shit wrong with my car mode" I'll be swapping out my pcv valve this week. I take it, it's a pretty simple swap?

[Charles.waite]

Simple, yea, but very time consuming and frustrating

I'd drain the coolant and remove the Intake manifold. If take a bit more time, but saved me a LOT of backache and frustration. I removed my PCV the first time (to do a bandaid fix) with the manifold on, and the second time (034 silicon kit) with the manifold off and it was SO much easier removing the manifold. The working space is REALLY tight under the manifold and you risk snapping a nipple off the N112 or N249 working in those tight spaces, not to mention you need to get VERY creative with tools to get the various parts off.

Are you just replacing the valve? Also do you mean the pancake valve on the top rear of the engine? Thats the PRV not PCV. slightly different yet related function to the PCV.

[jayson161]

I was just going to replace the valve. I don't really have the space to work on my car more in depth to be draining coolant. Don't think the condo association would like me doing that in the garage. If I get the 034 kit, would you be willing to give me a hand installing?

[jayson161]

Turns out there were a couple broken pvc hoses attached to the breathing tube system which resulted in the pcv being clogged with oil. Hoses have been replaced, pcv replaced, plugs and valve cover gasket has been done. Hopefully this will be the end of it.

[SlickFix]

Turns out there were a couple broken pvc hoses attached to the breathing tube system which resulted in the pcv being clogged with oil. Hoses have been replaced, pcv replaced, plugs and valve cover gasket has been done. Hopefully this will be the end of it.

Yep, and that's what caused your VCG to go bad. A lot of people replace their valve cover gaskets and don't get the cause of the leak resolved. Good job!

[diagnosticator]

Audi issued a TSB about misfires at cold start up, the fix is an updated ECU reprogram. Should be free at the dealer.

[jayson161]

Audi issued a TSB about misfires at cold start up, the fix is an updated ECU reprogram. Should be free at the dealer.

Do you have a link or email about that TSB? I was just there Friday and they didn't say anything about it when I was telling them the issues my car was having? Would that reprogram affect my chip at all?

I think I spoke too soon as well about having my issues cleared up. The following day it was another rough start in the morning and my CEL turned back on.

[diagnosticator]

TSB 01-08-31 24, "Update Programming ECM to correct cold start misfire" A4 AMB. December 09, 2008 The update reprogram will over write the chip flash, so you will have to have the tuned ECU file reflashed to the ECU after the update.

[jayson161]

Thanks for the info. I might have a slight issue getting my chip reflashed though. I have a custom home brewed kit from a shop that I'm not 100% sure is still around.

[johnnyjumps]

were you ever able to figure this out? I am have the exact same problems.