I've come across something strange within the past few days. One morning, I went to start my car, and temps were about 20 degrees Celsius and warm up idle was 3000rpm. As the temperature approached 45 degrees, the rpms dropped down to 1800 suddenly and started pulsating. It began to stutter and seemed to flood itself out until it stalled. I looked at the max readings on my PFC, and it said boost was at +0.29 Bar, which was strange since I didn't rev it at all. Tons of black smoke came out and it all smelled like fuel, and the exhaust temperatures were still quite cold. I looked at I started the car again and it had difficulty starting, but I got it to start. The rpm raised to about 2500, injector duty was reading 13%, but I was sitting at +0.29 Bar of boost again. I revved the car to 5500rpm and my BOV released air as if it was actually under load. Boost was reading a max of +0.68 Bar. This can't be right.

I called my builder/tuner and he thought it might have been the MAF sensor. I swapped mine out with one I borrowed from a friend and the same issues were still there. I held the rpm at 3000 and injector duty was at 45%. I looked at the sensor check and everything was good. The engine itself only has 4000km on it, so I was losing my mind. I started it up again and let it run for a bit while I was trying to figure out what could possibly be the reason for it's strange behavior.

As quickly as it started, the engine lowered it's idle and sat at 1100rpm. Vacuum was at -430 of Mercury and injector duty was at 6.5%. I was a little afraid to test it at this point, but a tow truck would be about $40, so I decided to give it a shot. I went onto the local Express road and everything went together well under light load. I floored it in 3rd gear and acceleration was linear like before. Everything was fine.

I'm just wondering if anyone else has had issues like this? I'm thinking the ECU might have caused this and I want to get to the bottom of this situation before I drive 2 hours to a track just to have it towed back to my city. Also, is there an option on the PFC that allows you to build boost at idle? The reason I ask this, is because like I said before, air was released through the BOV as if the car was actually under load, so it made me think it was a little bit more then just a sensor malfunction. Thanks for your time.

 

The issue is your lack of understanding of all the tables/parts that control starting and idle. If your engine is stock, the stock map should not have any serious problems like you mentioned. If your engine is modified, then it is a tuning problem.

You did mention builder/tuner. Thus it might need cold weather tuning.
The PFC allows full weather tuning that once set, will not require any additional seasonal changes.