What was found
CLIMBING THROUGH 8500' FO PITCH & ROLL GUIDANCE WENT AWAY. "VTK" APPEARED ON FO'S ND, THEN RESET TO NORMAL. "F/D" SWITCH WAS SELECTED TO FO'S SIDE "ON". GROUNDED - YES. ACCOMPLISHED RT FMC COMPUTER SYSTEM BITE B737-900 FIM 34-62 TASK 801 RT FMC COMPUTER LOGGED SEVERAL FAULTS. INTERMITTENT WATCHDOG TIMER IN 5 FLTS. REMOVED AND INSTALLED NEW RT FMC COMPUTER REF B737-900 AMM 34-61-02. PERFORMED SYS TEST STEP E INSTALL TEST. ALL SW LOADED AND ALL TESTS PASSED. PERFORMED FMCS PERFORMANCE FACTORS - ADJUSTMENT, AMM TASK 34-61-00-800-801 AND FLIGHT MANAGEMENT COMPUTER SYSTEM - OPERATIONAL TEST, AMM TASK 34-61-00-710-801. SYS CKS NML.