Steven Petersen
I'm Awesome
I wasn’t referring to df2x4. He gave a useful answer.Good job being outraged for someone else.
df2x4's answer was accurate and not a lecture.. in fact I didn't see any lectures, except you lecturing us, so now I'm lecturing you about lecturing.
Unplugging the vacuum line to see how it responds isn't an effective test. If the spring inside the EGR valve is broken or weak, it can still open on its own, partially functioning (generally when it should not.) A true test to see how it would act when removed, is to...remove it, and install a block-off plate.
Retarding base timing a little bit may help prevent ping. A custom tune to address spark advance would do better. It would also cost a lot more than simply having a functioning EGR.
Richard