finally got the z running turns out the opti was drenched in coolant. but i have a new prob. it was going on b4 the other opti died. when the car is cold it runs fine then 2 mins later the service engine soon light will come on and the fans go on. then it starts stumbling and bucking. no backfires or missing just that. but when i go full throttle into it. the car clears up. but anything lower it will run crappy . btw its getting real poor gas mileage too. any suggestions are greatly appreciated. also it stalls too. and i have to put the pedal to the floor to get it to start. already did the unpluggging the mass air trick the probs still there.

 

could a bad 02 sensor put the car into limp home mode along with a ses light?

 

The SES is telling you to read the codes. You need to have it scanned.