I got the engine installed around 3 months ago. I changed the distributor, plug wires and plugs 3 days after. NGK wires, Denso iridium plugs and Bosch distributor. I just diagnosed it again awhile ago. When it was losing power and the RPMs started to drop I clutched in and kept my foot on the gas. The RPMs bounced back and forth between 3000 and 3500. The check engine does come on but not right away. It takes awhile for it to come on, sometimes never comes on. I do have a broken speed sensor, don't know if that has anything to do with the check engine light.