You need FIX the problem first

 

huh ?

 

Well Cobb doesn't support crosstreks, so that's another obstacle.

 

I just replaced the oem part for 330$ for the part. I don’t have any way of programming for a delete so that’s that .

 

you would use subaruedit and a tactrix. Cobb is especially useless with NA vehicles.

 

2018 Crosstrek , I haven't confirmed it yet , but do believe that the many EGR valves are failing and Subaru knows it. I hear on occasion clattering on the passenger side that sounds similar but not exactly like Pre ignition or LSP. It went away after I disconnected the battery, like it maybe did a hard reset on the EGR valve? As usual dealership said no code and don't have many failed EGR valves. Next time I drive it and it starts clattering , im going to pull over and disconnect the plug to the EGR valve and see if it goes away.

 

First thing I would try is a "Top Engine Cleaner" Seafoam/Subaru. You spray it into the intake with the engine running.
Odds are you have not been using top tier gas with additive or using "injector cleaner" additive (Techron, etc) regularly and carbon has built up in the combustion chamber creating hot spots.

 

What is the benefit of egr delete?

 

Increased pre-ignition -"spark-knock"
Reduced power from timing/throttle being reduced to control pre-ignition.
Poorer temperature control of air/fuel charge.
Hot spots in cylinders that cause pre-ignition.
Increased oxides of nitrogen.
Poor performance from all the above.

Cut out a block-off plate from a beer can and put some electrical tape over ALL those warning lights because science and physics is optional these days.

 

Then why are so many people doing it? Pre ignition from lack of hot exhaust gases? What about blocking egr causes pre ignition?
Isn't temperature controlled by a coolant system? How would lack of hot exhaust gases make it harder to control the temperature?

I'm just trying to understand how all that happens.
I understand pollution increase, since exhaust gases aren't burned off completely, but the rest just don't make sense to me.
Can you explain in more detail please?

 

You don't want EGR at idle or cold start - the car would run too rough/stall. Wide open throttle is open loop operation - you are throwing so much fuel in the cylinder the fuel quenches it. Cruising is a steady state under minimal power demand. You can also retard timing which is exactly why you hear the turbo boys talking about "pulling timing"