We have a 2008 Chevy Suburban LTZ Flex Fuel, 220,000 miles. It lost all oil pressure and started making a clicking noise/maybe knocking noise that got louder the harder you push the accelerator. A week or 2 prior it started backfiring or poping in the motor intermittantly. We really want to fix it but will have to do it ourselves. Do you think it can be fixed or do we need a new motor? Where to start?? I have a video of it running but do not know how to upload it here.