sr20det timing issue!

[Speedrush]

Hi guys! I have a question i really need an answer to..
I have a s13 sr20det blackrop in my 90 coupe and when i check the timing with a timing gun it is waaayyy off. Like at 25 degrees or so and when i try and set it to 15 deg the engine starts bogging and wants to just die. It otherwise idles awesome...
here is what ive checked and done... i have opened the valve cover and made sure that it isnt off a notch. I turned it over to tdc and the notches on the cams line up perfect just like the frsports illustration directs. Then i pulled out the CAS and reinsered it accordingly as well..the left notch and the mark on the shaft line up perfectly. the TPS is set at 0.52v which should be right in the middle. When i crank the car it warms up and drops down to about 850rps and idles like a charm. I check the timing by unplugging the TPS reving the motor couple of times to lock in timing and hook the gun to the loop on the harness against the firewall behind the motor. I have tried everything bjt cannot get it to get even close to 15 deg. I am not off a notch i have triple checked that already. Please if anyone has any input feel free to comment...any info would b greatly appreciated...also i have greddy style manifold...stock t25 w 14psi