One more thing I would like to add is injectors are new, and injection k-tronic was rebuilt. I only have about 1500-2000 miles on those parts. And when I start it when it's cold it idles up for a second then almost stalls for second then idles back up. Not sure if that has anything to do with it but I thought I should add that.

That version of K-Jetronic incorporates a closed-throttle coasting fuel shutoff; when the throttle is reopened the resumption of fuel flow can cause the pop.


The two are linked; likely the overall mixture is a bit lean. The start sequence may have cold-start injector fuel present, then that is exhausted, then the Warm Up Regulator (WUR) picks up the mixture.
The pop can be caused by a lean condition when the fuel flow resumes; the air flow increases faster than the fuel flow, leading to a brief leanness.

[As to your other post: Expect engine water temp to vary between 80-100C., depending on ambient conditions, and power demand (climbing a grade vs. descending).]