Thank you for the info.

Quote Originally Posted by tayto View Post
D1984A is the "395" module
D1945A is the "048" module

395 is the one to get. apparently gm discontinued the 048, so i've always wonder if both Delco numbers are the same module but never had the time to check with a timing light.

if you datalog just follow the troubleshooting flow chart in the pdf. my method is if you only have a paper clip in your tool box...

EDIT: aside from regular tune up items, I usually consider the CTS part of a "tune up" item for TBI. usually for my own vehicle or if someone brings me something that has been neglected or not running right. Also consider the same for the O2 sensor, I usually upgrade to a heated O2 at this time.