hi i have a 1991 camaro rs 305 tbi. just rebuilt to stock except cam,headers,no cat,chip and all new sensors. the problem is when it warms up the idle goes very low and high and sometimes stalls. i figure it would be something with the 02 sensor witch is brand new so when i unpluged it and it ran fine so i went out and bought a new one and the same. i herd something that i need 3 wire plug or adapter. any help? thanks alot for everything you guys are great help.

 

Double check vacuum lines. Is the chip you used a custom burnt chip exact to your mods? If it is just a "plug and play" chip, it may not be suitable, especially with a non stock cam.

 

its a hypertech chip. i have all new vacuum lines and i triple checked them all. the engine runs fine when the 02 sensor is unpluged. when its pluged in its very loopy up and down and stalls.

 

A daying fuel pump can also cause unstable idle. Low fuel pressure would confirm.

 

i check my fuel pressure while the car was running it was around 12. i did not noticed the pressure moving it stayed the same the whole time.