rough idle when cold and surging idle when warm

[BWeston]

on start up, my car idles very rough and usually goes dead if you dont give it gas -- until it is warmed up about 1/3 of the way to normal. Also when it is warm, when stopped, the idle surges from anywhere between 1300-2000rpm. we have changed a temp sensor, and double checked the vacuum lines for leaks, and are planning to change the o2 sensor first chance we get, i hope that helps. but any other suggestions or leads to what may be the problem as well?

P.S. I'm not sure if this will offer very much to help, but my car is a 2g running on a 1g motor, the 2g motor had been taken out and swapped for the 1g due to issues with the 2g generation of motors.

 

[Gasolinebaptism]

Okay, you need to test the ISC warm. the ISC is a plug on the back and bottom of the throttle body, facing the battery. unplug it, there is 6 pins, and 3 coils. you need to test resistance and it needs to be around 30 ohms when the car is warm. the coils are between 1-2, 3-4, 5-6. I think, if not, just connect your needles til you get a reading. if resistance if too low then get a new one from DSMISC.com.
It could also be the FIAV. but the ISC is your first stop.

 

[DSM1G90]

If no CEL light, might be the ISC motor giving you fits... If there is also a CEL, could be the ECU is beginning to dump on yas ...

 

[BWeston]

ok, thanks for the info. i will get to that as soon as i have time this week.

 

[Gasolinebaptism]

No problem.

 

[BWeston]

@DSM1g90, my check engine light is also on, so if thats the case then it must be the ecu screwing up on me. is that not a common problem with the dsm?