I changed my Timing-Chain rail guides one day because holy-crap, if you guys haven't done it by 100K miles, you REALLY should.

Car ran like a champ for 2 days and then all of a sudden, out of the blue it started feeling sluggish and it popped a P0172 (System Too Rich) with a P0108 (Manifold Absolute Pressure/Barometric Pressure Control Circuit High Input), I took a look at my Wideband and sure enough, it was running a tad on the rich side but most noticeably right after coming off-throttle or when I first get at idle it gets pig-rich to 9.5:1 and car almost dies.

I checked my plugs, checked the IC boots, they're relatively brand new. I know that some mechanic awhile back changed one of my MAP sensors for something not OEM and I know those were critical so I got both Pre and Post Supercharger MAP sensors replaced by MINI sensors. Still... no dice.

I looked at my logs and was looking for the culprit...

O2 Sensors? Well, my O2 sensors are correlating exactly with what my Wideband is saying, and the voltages are correct, so it doesn't seem like that's a problem.

MAP Sensors? Well the temperatures are in line with ambient when off and they aren't giving me any weird readings. The AirMass isn't out-of-order either... they trace appropriately and similar to their previous readings when things were doing well.

I'm probably going to change the ByPass valve today because... I don't know... reasons....

But I can definitely see that my calculated load is WAY off... at idle it's 75%.

Question is, why? I know that the MAP sensors and the Throttle-Position are some of the sensors that have an effect on the Calculated load, but both are reading perfectly fine.

Any thoughts? I reset all my adaptations just in-case, but I am really tired of throwing parts at this.


Up to 75% load at idle.