Low Power under 2krpm, then Surge

[thenomisf]

Hi All,

I recently converted my S12 from auto to manual, but ever since it has had a weird "feature".

Under 2000/2500 rpm the engine feels good, but very dead on power (as you are pulling away), as soon as it goes over there is a very noticeable and sharp (almost feels like you have been rear ended) increase in power. It feels a lot like suddenly adding 5-10 degrees of timing.

This happens regardless of boost level or throttle position (and no its not just the turbo coming on, its a very sharp sudden change).

I have checked all my sensors and wiring, removed the auto trans electronics, I have no boost leaks. I can only assume there is a difference in timing map for the auto for smooth pull away (?) but I am told the maps are identical.

I am trying to get a timing light to check, but the service manual says auto/manual CA18ET should be timed the same ?

I am aware the knock sensor becomes active at 2200 RPM, but I would have though that would make it feel slower if it was retarding timing , but who knows!

Any ideas would be appreciated!