Hey guys, so I've recently tried fixing the idle surge on my CD5 and have ran into no luck. I've cleaned out the IAC and the FITV. The car wouldn't surge for about 4 hours and then would just randomly start up again. I heard getting a new map sensor might fix it but I'm unsure of how to reset the ECU. Any possible solutions you guys can offer would be awesome!

 

Idle surges are simply caused by a vacuum leak. Replacing parts won't fix the problem. What you need to do is to find the vacuum leak and fix it.

It could be a leaking vacuum hose, a leaking intake manifold gasket, leaking brake booster hose etc etc.

I very fine mist of water vapor will help you find it when you hit it with the car idling.

 

Or propane works too.
Turn it on (don't light it)
Then go around the engine intake, and vacuum lines. When the idle changes you found it.