I just had a question... I just put in a new d16 motor in my 89 dx hatchback. After the swap was done and i started driving after a while I noticed that my check engine light had turned on... I checked my ecu and it was flashing code 1. I found out that it was the first o2 sensor was the code that was basically flashing at me... So my question is this... do i replace it or should I look into other factors as well???

 

CEL says o2 sensor, so it must be. when is the last time the o2 sensor was changed? Try changing it out, if it happens again, maybe wires could be frayed or ripped.

 

well... I got the car about 6 months ago so I can't say for certain. I will take the advice though and replace it soon if not now...

 

replace it with a new universal ngk one from sparkplugs.com...it's only $18.88
http://www.sparkplugs.com/results_app.asp

 

do you think the tuning is off? I mean... when the check engine light is off it purrs like a kitten but the second the check engine light turns on it becomes sluggish... any thoughts?

 

I doubt tuning would be off cuz it comes on after you drive, and that you threw a CEL 1 which is o2 sensor. They aren't expensive, especially when it's the one wire o2 sensor. They are one of the first things to go IMO, and get clogged vey easily, and causes the motor to run like crap.