99 C70 Misfire

[ehinson]

The other day my c70 started missing for about 10 seconds, the check engine
light came on and the it stopped missing.

When I got home I connected a laptop to the OBDII connector with a DigiMoto unit I have, the fault code was Misfire on cylinder 3.

I replaced all the plugs the next day, started driving to work and it started missing again, then ran normal, I pulled over and hooked the laptop up again.

This time the code said Misfire on multiple cylinders.

Does anyone have a suggestion as to what the issue might be?

Distributor perhaps?

Just a note, I did have the ECU flashed a couple months ago for the recall, and apparently mine was affected because it was surging.

1999 Volvo C70 Conv, 66K

Thanks for any help!