New User: L98 Engine Trouble
No one has mentioned to check the timing. Just to verify where it is. Disconnect the EST connection while the engine is runing(this will set off the SES light on the dash, but you will clear it afterwards by disconnecting the battery for a few seconds) and strobe the timing mark. Adjust dist if necessary. Give a visual to the harmonic balancer's elastomer ring just to visually verify it is not separated(rarely happens).
At this point in your engine's life, get that coolant changed out and serviced regularly!










