Just replace pistons and rings, replaced broken connecting rods, oil pump, timing chains-guides-tensioners, the solenoids that are in the heads, all bearings, rear-main seal, and oil filter. It started up great but then after a couple of minutes the check engine light came on. We thought that was due to needing more antifreeze. Filled the antifreeze up and started the motor but check engine light stayed on. Then after a few minutes the RPM dropped and so did the oil pressure. If we kept the RPM at 1500 the oil pressure stayed up but there is knocking sound. The motor started up fine for the first 5-8 times but then it didn't want to start. Finally got it started again and the same thing continues except the oil pressure started bouncing down to the L and then back up.
Does anyone have an idea of what the issue may be?

Thanks

Kathy

 

What year? Is this a 2 valve or 3 valve?

 

2006 3 valve