I did a quick search and most of what I found was about 1.8Ts. When I start my car after it has sat overnight, it will have a rough idle for about the first minute or two and then it will be fine. If I try to rev it up during this time it will act like it's not getting enough fuel and is going to stall. This started happening a little over a month ago. After the first couple of minutes, it runs completely normal and doesn't have any hesitation at all. Any ideas? Within the last year I've replaced the coolant temp sensor, spark plugs, spark plug wires, driver's side cam position sensor, and some other things I can't think of right now. So I wouldn't think it would be any of those. I checked/cleaned my combi valves for the SAI over the summer and they opened and closed like they should.

 

Could be that one of the main coils is weak and is starting to fail. Check all your plug wires to make sure they are all connected tightly and not touching each other.

Are you getting a check engine light?

Jason

 

Unfortunately, I always have a check engine light because it is constantly telling me the main catalyst efficiency is too low. I ran vag-com and got back about 6 codes from the engine. I saved the log, closed vag-com, and then when I went to open the saved log it had somehow disappeared. So I guess vag-com decided not to save the log after all. I've already cleared the codes to see what comes back. From what I remember there was random misfire, misfire on cylinder 3, misfire on cylinder 5, something that said a fault and then said "probably fuel too low" or something like that. All of them said they were intermittent. I guess I'll have to drive it for a couple of days and then run vag-com again.

 

If its mostly missing on one bank it could be that the coil pack or the wires on that side are weak or failing.

Jason

 

Did you try cleaning the Throttle Body?
Scratch that........I thought you were 1.8t, see that you are not......

 

Still have the same symptoms. I ran vagcom again and got this back:

Address 01: Engine Labels: 078-907-551-AHA.lbl
Part No: 4D0 907 551 AH
Component: 2.8L V6/5V MOTR AT D02
Coding: 06251
Shop #: WSC 06335
VCID: 6CD3C083344B

10 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
16795 - Secondary Air Injection System: Incorrect Flow Detected
P0411 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
16806 - Main Catalyst; Bank 1: Efficiency Below Threshold
P0422 - 35-00 - -
16689 - Cylinder 5: Misfire Detected
P0305 - 35-10 - - - Intermittent
16689 - Cylinder 5: Misfire Detected
P0305 - 35-10 - - - Intermittent
17708 - Misfire Detected. Probably Reason: Low Fuel
P1300 - 35-10 - - - Intermittent
17708 - Misfire Detected. Probably Reason: Low Fuel
P1300 - 35-10 - - - Intermittent
Readiness: 0000 0100

I also ran vagcom while I started the car to watch it for misfires. It didn't show any for about 10 seconds and then it started showing misfires on cylinder 2 and within a couple of seconds it totaled 14. I ran the car for couple of minutes and it never showed any more misfires. I put some stuff (can't remember the brand name) in the gas that was supposed to take care of any water that might be in there. I've run through a tank since then and it didn't help any. I checked my spark plug wires and they look good.

 

It's been a while but the problem still persists. I changed the ignition coil pack and it didn't make a difference but it did make the P0422 and P0432 codes disappear. I changed the fuel filter which was more than 50% clogged and it cut the rough idling time about in half and got rid of the P1300 code. I tried the fuel pressure regulator thinking maybe it wasn't getting enough fuel pressure but that didn't change anything. I checked the air filter and it's still good. I pulled the cylinder 2 spark plug and it looks brand new aside from being a light brown color. I checked and it has about .036 gap. The resistance of the cylinder 2 and the cylinder 1 spark plug wires are within about 400 ohms of each other. I can't find anywhere that looks like the spark plug wire is arcing. I pulled the intake air temperature sensor and the MAF and sprayed them with MAF cleaner. None of that made it any better. I now have these codes:

Address 01: Engine Labels: 078-907-551-AHA.lbl
Part No: 4D0 907 551 AH
Component: 2.8L V6/5V MOTR AT D02
Coding: 06251
Shop #: WSC 06335
VCID: 6CD3C083344B

5 Faults Found:
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-00 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-00 - - - Intermittent
16684 - Random/Multiple Cylinder Misfire Detected
P0300 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
P0302 - 35-10 - - - Intermittent
16795 - Secondary Air Injection System: Incorrect Flow Detected
P0411 - 35-00 - -

My thought now is that it has to do with the SAI system. I checked/cleaned my combi valves over the summer and they work like they should. The solenoid that controls the vacuum going to them works. I think the pump may be bad and it is allowing the exhaust to feed back into the intake by way of the air box during the time the combi valves are open. This makes sense since when cleaning the MAF I noticed that the airbox side of the screen was turning from black to silver as I sprayed it. I'll have to look into that theory some more tomorrow but does it sound like that could be possible?

 

Unplugged the solenoid that opens the combi valves this morning after the car had sat overnight. Fired it up and no misfire. So obviously the air pump isn't working but the combi valves are and it had been feeding exhaust back into the intake. I checked the relay in the ECU compartment and it is good. It didn't have any power at its connections though. Couldn't find a fuse in there. Did some looking around at the relay panel that's under the dash on the driver's side. All of the fuses under there were good. Then I found an open spot for a large fuse. Put a fuse in there and now I have power at the relay in the ECU compartment. Now just need to hook up a 12v source to the air pump and see if it works. I doubt it though as the car has been driven like that for at least a year and a half. Previous owners must have removed the fuse for some reason. I know its not a big deal to get the SAI system working again but I would just really like to get the CEL to shut off. I'm tired of looking at it.

 

Ran the output test through vag-com. The air pump is running, amazingly. It's pushing lots of air. About like a hair dryer. So I think it's fine as far as it running. However, the rivets that hold it together are loose so I need to take the pump out and replace them with bolts. But I can't easily see how to get it out. According to the Haynes manual, you have to remove the bumper and put the front end in service position. Surely there is an easier way than that. Anyone removed one on a 2.8 and know how?

 

Well, I was able to unbolt the air pump from the bracket that holds it. However, I couldn't find a way to get it out of the bracket and out of the car. There wasn't enough wiggle room to get it out. So I ended up having to remove the bumper and put the front end in service position. Then unbolted the bracket from the car and removed the motor and bracket together from the car. With the bumper and front end out of the way there was plenty of room to get them both out. Might have been able to remove the motor without removing the bumper and everything but it probably would have taken just as long to figure out how to get it out as it would have to remove the bumper and put it in service position. Now I just have to drill out the rivets and replace them with some bolts and put it back in the car and P0411 should be gone. Finally.