I have a 1993 Nissan 240sx. I just got an oil change and all of the sudden while accelerating I hear clicking. The more I accelerate the faster the clicks. Acceleration seems sluggish...like something is clogged. Added seafoam to a full tank and today it was still clicking. choking lke it didn't want to stay running, and now won't click into its automatic second gear and the rpms are at 4000. WTH?