My 90TII has a Mazda Reman with about 4k on it. It is stock except for an intake. Under hard acceleration (about 5psi) there is a ticking sound that I can feel through the shifter. I am hoping it is not the dreaded ping but am not sure exactly what that sounds like. I can slowly take it up to 5k rpms or so without any sounds. Can anybody have help me out.\


Again, as long as I'm not under full boost it won't do it.

 

One other thing, the check engine light does come on after I drive little while. I pulled two codes.

17 feedback system (oxygen sensor output remains 0.55v 10 sec. after F/B system operation beginning)
42* Duty solenoid (turbo boost pressure control)

 

id check that control. When i hooked the actuator up to a direct vacuum source it would make that sound like the turbine was scraping the sides of the housings.