Stumped on 300zx problem, runs funny when cold.

[yoozef]

My car runs like crap when it's cold and after 10 to 30 minutes of driving, it drives fine. It's a 1990 TT. Sometimes when i start it the car shakes. I thought it was misfiring, changed spark plugs, but the problem still exists. I thought it might be a headgasket leak, but would it get better after driving for 15minutes? Would worn oxygen sensor cause this? If anyone has any ideas, please help, thanks nico

[freakonaleash1187]

Have you ran an ECU diagnostics?

I know there is a "cold loop" and a "warm loop" the ECU runs on, there might be something wrong with the "cold loop." O2 sensors could also be doing it.

[yoozef]

do you need the computer or is it something like flashing lights on the dashboard? i just made an appointment for the free 15 point free check up at the nissan dealership, so hopefully they'll do that, i also forgot to ask, i was reading online that theres a method to clean the oxygen sensor, has anyone done it and what did you use? thanks