well its been a week, ive replaced the plugs changed the gap to .028, did the boost leak test to 21psi, cleaned the air filter and turbosmart bov, reset the computer tightened all clamps again, did notice during the boost test the throttle body is leaking at the shaft. i order the new orings and gasket for replacement. the shudder is completely gone everything drives and boosts normal. dont know which one of these things caused it but it was one of them i did them all at the same time. i just wanted to thank all you guys for your inputs and suggestions