I have a '99 d16y7 and while im driving my car the rpms will drop down to around 450 when i come to a stop or push in the clutch. the lights will dim and the car will act like its going to die. it doesnt do this all the time, just randomly it seems like. Any ideas?

 

I had a similar problem on my old '90 Civic Si. I also had a very slight surge/lag when cruising at a steady speed about 25mph in 3rd gear. In my case, the O2 sensor was slow/lazy. That was screwing up the fuel trim. An OEM sensor solved the problem after two Bosch generics didn't.

 

Check/replace your grounds

 

These civics have a problem with the alternator's (If not already replace under warranty back in the day) so make sure its putting out the correct voltage (about 13-15 volts at idle no load).