I'm at the crossroads where the mechanics will neither give me good advice or bad advice... after reading the context below, please tell me if I should ditch and get a new car??? Tyvm.

Timeline of Events & Notes from my Journal/spreadsheet....
9/3/2021, 172,500km All Spark Plugs replaced w/ DENSO 3457 due to mileage (no errors)
10/11/2023, 183,250km CEL on, diagnostics codes P0106, P0302 started
11/13/2023, 184,000km All Ignition Coils replaced, MAP Sensor cleaning, Throttle bodies cleaning, vacuum leak check, etc. w/ HITACHI IGC0078, DENSO 1433068 (143-3068)
***sometime in between these dates, the P0106 and P0302 lights came back on and we found small bit of oil on the spark plug in Cylinder 02.***
3/31/2025, 196,800km Oil change, Replaced Valve Cover Gasket, Intake Manifold Gasket, Throttle Body Gasket, PCV Valve due to mileage and caution (and due to small oil leakage found last time)
7/10/2025, 200,800kmSymptoms: Heavy, uncontrollable shaking coming from the engine that could be felt through the steering wheel and driver side, during startup and idling and entire trip, to the point that the CEL would flash constantly (I have never experienced this before). After driving it like this for a day and a half, I left the car in another shop (I see 2 shops, whichever has time for me first). They said there was a major oil leak that contaminated all spark plugs. They said I need to order a new Valve Cover & Gasket.

This is the crossroads that I'm at now.

-Valve Cover replacements are not common right??? So what happened?? On 3/31/2025 I already replaced all the gaskets out of caution and old age.... thought i was doing the G a favour
-OEM Valve Covers & Gaskets are not cheap, I'm seeing $1300 CAD~ for Left & Right, and one side is backordered from official suppliers and the aftermarket versions from RockAuto USA and AutoZone (around $500 CAD in total) are also backordered.... WTF
-This is not a cheap fix, and while this fixes one problem, it doesn't actually solve the root cause which is P0302 02 misfire and P0106 to a lesser degree
-My spark plugs, or coils - could they be bad, defective, or need replacement?!?! Even though they are all pretty new and recent jobs?? (Apparently they swapped the plugs from one to another but it still misfires rough during startup/idle)

Has anyone experience with this? Is it time to ditch the G and look for a new car????

 

Can anyone recommend a valve cover???

 

Valve covers, gaskets and tube seals: https://www.z1motorsports.com/cylind...t-p-25174.html

 

Sadly it seems that there is not one modern engine today that does not- or will not- have a valve cover oil leak to some degree. A neighbor just had to go through this with her Merc and, of course, the dealer murdered her wallet. Why this is so difficult for engine designers is beyond me.

That said, being you are in Canada, it will likely be significantly cheaper for you to order the parts from Japan. I just did a check and, no offense to the Z1 kit, but the same parts from Japan cost ≈$445CAD. Even with shipping/ import fees/ tariffs/ whatever the hell they're called this week/ this shouldn't cause too much stress on the wallet but then I do not know your situation.

As of 27 July 2025 from amayama.com:



Just pointing out options... but, yes, valve cover leak issues are, sadly, common place with these modern engines.

 

Z1 is just easy as they are well indexed on google. There are always less expensive options if one is willing to research.

I was surprised that they made a kit for this as I never thought that the valve covers themselves would need to be replaced. Tube seals and gaskets seem more prone to leaking and those are likely available from any auto parts store, but the covers as well?

While you have them off, you can upgrade to some aluminum ones painted red: