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ShadowofBob
08-07-2013, 07:48 PM
My 2000 ATW that has been converted to an AWM for all intents and purposes has a very slight miss at idle that sometimes exhibits itself as a hesitation when the car is cold. No codes are stored and I've I smoke tested the entire intake and can't find any leaks. It has a 034 harness repair kit, 2.0T coils, new BKR7Es at .030. I just tested the combination valve and it holds vacuum and doesn't allow air into it when closed. I adapted the throttle body this morning, and it was cleaned 5k ago when I replaced every vacuum line and check valve on the intake along with redoing the PCV system.
MAF sensor is 10k old Bosch.
WB02 15k miles old.
The 415cc Genesis injectors I have were purchased from a forum member as new, but I haven't had them flow matched or anything so I am not sure if they would really be the culprit.

Is there anything else that I've missed that could cause this or are 1.8T's just hard to get a perfectly smooth idle with?

Hamburger
08-07-2013, 09:03 PM
I had the same problem that just started today. It seemed to be as the ECU switched from closed to open loop fueling. The closed loop (just after start up, using the fuel trim input from the last time the car ran) caused a small hesitation, smaller then a misfire, but definitely something I could feel every two or so times all cylinders had gone through a cycle. upon feeling this for 30 seconds or so, it stopped as it switched fuel trims (went from about 940 rpm to 900 even). I plan to check my coils and o2 sensors, other then that I don't know where I might want to look.

ShadowofBob
08-08-2013, 06:24 AM
Yes, I think the hesitation primarily happens during the closed loop during the first 30 seconds on a cold start up whne the car is idling at 1200 RPM. The miss happens or is more noticeable after the car is warmed up and is at its usual 800 RPM idle.

audi-medic
08-08-2013, 06:31 AM
Yes, I think the hesitation primarily happens during the closed loop during the first 30 seconds on a cold start up whne the car is idling at 1200 RPM. The miss happens or is more noticeable after the car is warmed up and is at its usual 800 RPM idle.

Did you align the throttle after cleaning? It makes a difference on idle

ShadowofBob
08-08-2013, 10:23 AM
Did you align the throttle after cleaning? It makes a difference on idle

Yes, I aligned the throttle body most recently a week ago after changing out my plugs and coil pack harness since I had the battery unplugged.

ShadowofBob
08-14-2013, 01:14 PM
bump. Any more thoughts? What are the vag-com channels to check for misfires on each cyl?