Originally Posted by
sss4me subscribed. i'm n/a and have exactly the same issues. once the issue happens, if your doing like 30-50mph, you can put your foot on the clutch and off the accelerator and coast down the road, and it will bounce between 900 to 1500/1800 continually. once once the car is stopped, it will eventually settle down.
john is helping with mine atm.
how could bleeding the coolant system help with this? do you have a q45 t/b?
well because the ecu is reading the coolant temp sensor from cold start to warm, if you have air in the system this can affect the readings and the ecu is monitoring the coolant temp sensor in conjunction with the idle tables, so if there is air trapped inside the system it might not let the car warm up to operating temps which in turn will not let the ecu go out of closed loop or down to operating idle. i had this happen on my aem ems, this is much the same the cts is working in conjunction with the iacv through the ecu so as you can see there could easily be idle issues given those facts.
just bleeding the coolant and making sure there is no air insures this is not the problem, the coolant temps will warm up, iacv will respond accordingly to the ecu tables and that should rule out the cts chain of command. but i would say it would rarely fix the issue, but its worth a shot.