I changed oil and fuel filters and in the process lost around half the rpm's. I do not have a code reader nor do I have a owners manual or repair book.

I changed oil and fuel filters and in the process lost around half of the rpm's. I checked for leaks around the filters and everything is dry

Ensure you filled the oil to the top line on the dip stick, since this can affect fuel pressure. Beyond that, this link may help:

https://www.askmehelpdesk.com/cars-t...ml#post1415281