B6 A4 1.8t Vibration under Acceleration at freeway speed, misfire codes.

[chrisdeaner]

So I recently did a lot of the vacuum system work covered in a4darkness' amazing thread and the car was starting to run well. CEL was back but it was same combo of codes I had gotten awhile back that is most likely coming from a bad PCV (the one under the intake manifold, not the "puck" which I replaced sometime back).

Anyway coming home on the freeway the other day I noticed some pretty serious vibrations when on the freeway and accelerating. It got really bad while going up a pretty steep grade but as soon as I took my foot off the gas it immediately stopped. At "around town" (45 and under) I don't feel anything abnormal, I was even trying to push it with hard acceleration up a hill from 25-45ish and felt nothing. Only on the freeway is it coming back. It's also not consistent which is leading me away from bad CV joints - I tried to replicate it yesterday on the (empty) freeway going down to 55mph and up to 75mph several times with nothing abnormal.

I pulled the codes yesterday and got the below:

Address 01: Engine Labels: Redir Fail!
Controller: 8E0 909 518 AF
Component: 1.8L R4/5VT G 0002
Coding: 0016751
Shop #: WSC 63351
VCID: 749B5FD357A3
7 Faults Found:
17978 - Engine Start Blocked by Immobilizer
P1570 - 008 - Implausible Signal - Intermittent
16684 - Shareware Version. To Decode all DTCs
P0300 - 008 - Please Register/Activate - Intermittent
16685 - Shareware Version. To Decode all DTCs
P0301 - 008 - Please Register/Activate - Intermittent
16687 - Cylinder 3: Misfire Detected
P0303 - 008 - Implausible Signal - Intermittent
16686 - Shareware Version. To Decode all DTCs
P0302 - 008 - Please Register/Activate - Intermittent
17519 - Shareware Version. To Decode all DTCs
P1111 - 002 - Please Register/Activate
17544 - Fuel Trim: Bank 1 (Add): System too Lean
P1136 - 001 - Upper Limit Exceeded
Readiness: 0000 1001

The P1111 and P1136 have been hanging around for a bit but those aligned to what I had awhile back where oldguy recommended replacing the PCV. That's on my to-do list just deciding if I want to shell out the $140 for the 034 kit or chance it with just the $15 OEM replacement and pray none of the hoses disintegrate.

All of the misfire codes are brand new. Awhile back the car completely died on me and long story short the shop replaced the suction jet pump along with the spark plugs, coil packs and harnesses so I don't think it's related to those but trying to see what else I should be checking related to the mis-fires.

Appreciate any help!

[chrisdeaner]

Welp I think the vibrations are due to a bad left CV boot/joint. While inspecting the engine for obvious issues I put a glove on the left CV boot and could completely expose the joint. Funny thing is it's still really inconsistent as I took it for a drive today and was at highway speeds and had 0 vibration issues up to 80mph. Now just have to decide if it's worth replacing or if this is the final straw for this car.