So, I bought an 09 r56 s turbo, with 116k miles which already had the timing chain replaced at 105k, upgraded intercooler, colder plugs and 2 in charge pipe installed. I went ahead and changed to a catless downpipe(which I heat wrapped) bought the upgraded bov and replaced the spring with an alta spring, changed the oil and filter to 40 weight and had it tuned by mariokart. Use 93 octane and seafoam treatment

So here is the weird......
Car starts up and idles just fine. I can even get in and drive immediately no issues. once the car hits a certain degree (which I have no way to tell what that is yet since there is no gauge) it starts to surge like its a bad idle control valve. I charge the turbo a few times to get it warmer and poof its gone until the car sits for about 4 to 5 hours and then go through it again. Doesnt seem to matter if its cold or warm outside. Had some 70s and some 30s here in the last 2 weeks. No engine codes.

My inclination is to get a new IAC but does anyone else have any suggestions before I throw parts at it.

 

A couple years ago I had a similar problem --- cold start, any outside temp, car ran fine for a few minutes, 'til a specific timer in the ECU timed out. At this time, the ECU expects the engine to be at some specific temp --- mine wasn't, so it reacted badly. This happened after a minor tune adjustment and was easily corrected by my tuner (not Mario). Something to do with the new coolant temp adjustment of about 175 deg F. Mario should be familiar with this situation.

 

Sounds like an issue with the ECU. Wouldn't be surprised if it has to do with the catless dp and the tune. Until the engine reaches xxxx Temp it disregards the reading from the 02 sensors once its up to operating temp the o2 sensors kick in and adjust fuel trim.

 

Hi, if I were you I invest $20 and get one of the OBD2 WiFi or blue tooth depending on your phone and dashcomand in your play store app so you can monitor all that is happening in your car.just do a search in the forum. OBD2 and you can find all you need to monitor every thing on your phone.
Ben