Anthony Maggiore

Replaced all 4 spark plugs on my 2012 A4. Nothing was wrong prior to replacement, just figured I’d put brand new ones it at 80k.

Tried NGK 2667 1st. Worked fine for about 30 miles then then the check engine light came on and it started studdering and shaking during low revs.

Went and got NGK 1675 plugs and swapped them out at the recommendation of other forums. Worked fine the first start up this morning. Was running great. Let it sit for a few hours, went to start again and it shakes bad and the check engine light is on again... back and forth from flashing to not flashing.

any recommended tries before I take it to the shop?

jagtoes

Typical questions are do you have any OBDII codes. If so what are they. Also I just replaced our kids 2015 with 1675 so that shouldn't be the problem. Go back and check your work and make sure the coil connectors and the coils are as they should be. Strange that you get shuddering and shaking without any codes.

Anthony Maggiore

Pulled codes P0303, P0353. Went down to Autozone they told me Cylinder 3 was misfiring and the coil was bad. Replaced the coil with whatever they had in stock (duralast?) and it made the car worse! Swapped the coil back for the original and still have a check engine light on, still same issue. I noticed the connections do not click in on the connectors... seem a bit loose, but I've pressed them together as hard as I can.

SCarGuy

what plugs came out of it?

coils should def lock/click in place

Anthony Maggiore

Bosch plugs came out. Coils definitely "suction" into place, but the coil connectors for some reason don't seem to "click" when you push them all the way together?

SCarGuy

I've found these cars can be very finicky when it comes to plug choice - idk why. Where I'd always run NGK's in my Japanese cars, the Euro ones (most have been Audi's, 1 was a VW) always got Bosch. Same with my BMW's. So take that fwiw.

The clip not clipping sounds like an issue - check both sides of the plug, make sure the pins aren't pushed back. Is the little lock tooth clearing the tab?

Anthony Maggiore

Got engine codes
P0300
P0353
P0303
P2306
P0351
P0301
Recommended repair according to the code reader... inspect faulty vacuum hose? Only thing I did was replace spark plugs...

SCarGuy

Anthony Maggiore

Attached pics...

I did inspect the coil pins. They all look ok. I made sure the coils "clicked" into the harness on CY1-3 but I cannot get CY4 to click. See attached pics...
ot s
I cleared all codes and drove about 10 miles with no issues anymore and no check engine light coming on. Not sure if I should continue to worry about it now?

Anthony Maggiore