You can't simply put a different engine in there. You have a computer operating system that is engineered for one engine and one engine only, not to mention it would be against federal law to attempt that anyway.
That system is highly dependent on oil condition and viscosity so if you have been lax with oil changes and oil type you will have problems. I would suggest changing the oil using a high quality 5W20 oil.
Saturday, April 5th, 2014 AT 4:19 AM