My mechanic said I have a bad ECM and needs to be replaced, so I'm looking into doing it on my own, and the price difference is significant. A used one for my car (A 1997 Honda Civic, Manual transmission, DX) runs around 100$, and a new one for around 650$. Obviously buying used is a risk, but I feel like I could probably buy 5 used computers, and one of them is likely to work, and I still would have spent less than buying a new one.

Have any of you had any experience in this area?

 

I had a used one installed in my 94 a year ago and it has been fine.

 

Shouldnt have a problem. It is rare to see a ECU/ECM go back to be honest.

 

Used are fine as long as it hasn't been tampered with internally (i.e. "chipped"). You can't chip your particular ECU anyway though so tampering is doubtful.