Car jerking at light throttle + P0441. Related?
 

Ok, so I'm new to Audi. A few weeks ago I bought a 2003 A4 3.0L and it just had the clutch replaced. When I was driving it home, it threw a P0441 incorrect purge flow code. I cleared it and it was fine. I changed the timing belt, water pump, tensioner, pulleys on it last weekend and when I started it, it was misfiring on 2 cylinders. I changed the plugs and moved the coils around and that cured it.
A couple of days later the P0441 code came back. I cleared it again and it didn't come back until the next day. I drove it on the interstate for about 100 miles and cleared it again but it came back an hour later. I'm not sure where to start on fixing it. I wasn't too worried about it since it's just emissions but the car is starting to jerk.
When it's just cruising at a constant speed it will intermittently "jerk" (feels like the engine is cutting out). It's a totally random event but it will NOT do it when I'm off the throttle or at full throttle. It will only happen at light throttle. This happened once on my way home from buying the car (before changing the timing belt) but didn't feel it again for a while. The morning after the TB change it happened again but ran fine the rest of the week. It started again and progressively worsened this weekend as I drove it about 500 miles out of town.
I think it's an engine problem and not a transmission (6 speed manual) issue but I'm not sure. Could the P0441 and jerking be related? There are no misfire codes, so am I wasting money by replacing coil packs? (They were replaced under recall about 13000 miles ago)

Any help would be appreciated. I have some mechanical experience but not on Audis

Thanks

geez, tough one... i am pretty sure that the p0441 code is unrelated though. no other codes? sounds almost like a shot torque converter on an automatic car, but you have a manual.
do you trust the mechanic who did the clutch install?
i am wondering also, if a check valve may be starting to fail.

as i think about it, maybe my best guess would be to change the fuel filter. this is good maintenance anyway, and as is my usual practice, i always think about the 3 key ingredients, air, fuel, and spark. you said recent coilpacks, and new plugs, so i am doubting spark. air, well, you don't have any codes that would indicate a vacuum leak, and i am assuming that you have a clean air filter? (if you are not sure, check to make sure), and that leaves fuel.... change the fuel filter, make sure you don't have a tank full of bad gas (as that can happen sometimes), and maybe run through some injector cleaner.

Thanks for the reply.

The air filter is not new by any means but you can still see light through it so I can't see that being the problem. Like I mentioned, I did have some problems with the coil packs when I did the timing belt but I'm not showing a misfire...
I'll change the fuel filter anyways but I would think the symptoms for that would be different, like loss of horsepower and such. I just ran fuel system cleaner hoping it would help but it's only getting worse. What check valve are you refering to?

The clutch was done before I bought the car so I have no idea if it can be trusted or not. I'm gonna call the dealer tomorrow and ask him where he got it done. One thing I noticed is that the gear lever moves a little bit when I'm on the throttle compared to no throttle. Is that normal on these cars?

There are little check valves inline along many of the vacuum lines. Most are grey and black. But, these may only be on the 1.8T, I am not sure (though it would make sense to only be on the turbo engines as there is no positive boost pressure in an NA car which would require a check valve I guess)
almost anything else I can think of would throw a code.... Do you have Vag com? If so, check to see if you have any pending codes which have yet to light a CEL.

I don't have VAG COM but I think I'll buy one. I found a cable and software on ebay for like $11
I've been scanning it with a regular code reader but I hear that doesn't show as much as VAG COM. Is that true?

jerking
 

when is doing it try moving the engine wiring harness on the passenger side by the firewall, very common to get the wires burnt
we see a good number of 02 sensor wires burn on the passenger side as well the air flow meter wires causing erratic driving situations that go away every time you reset them
hope this helps

Thanks, I'll check the wires when I get a minute.
It only does it while driving. It idles perfect so I don't think moving them would really help me but I'll look for signs of bad connections.