Car is a 1997 Chevy Metro w/150k mi motor. 1.0 3cyl. G10 5-speed
Hello all. I replace the motor on this car about 8mo ago because it threw a rod. I tried setting timing but the mark on the crank pully wanders high & low & doesn't stay put. Timing belt tension is tight, & I'm thinking it could just be bad carbon buildup in the combustion chamber causing pre-detonation. I'm going to pull the head, check it out & clean it. The thing that concerns me though is the head bolts are torque-to-yield & are not designed to be reused. Does anyone have any experience with reusing torque-to-yield head bolts without any problems?
The car has also been running too hot (3/4 on gauge) & has failed emissions with the NOx, Oxides of Nitrogen count of 1172 (964 is passing in NJ). I cleaned out the carbon from the EGR Valve & the passages of the hoses going to it, but no improvement on temp. when I tried to retard timing to try to lower the temp the idle died too easily. Has new fuel filter, new thermostat, new coolant temp sensor. No CEL light, nothing registering on OBD2 scan tool. Maybe bad water pump? If so is there any way to check if the pump is good while on the car? I know it may sound like I'm being cheap not forking up the $30 for new OEM head bolts, but I'm trying not to spend alot on this motor because I just need the G10 to last me untill next summer.

Any info anyone can provide is greatly appreciated.
-Vic