Hmmm. I'm sure you have checked all the usual suspects exhaust/boost leaks etc. I bought a Nytro with an MCX kit from a dealer who installed the kit, it was a 240 kit. It always ran like crap so I pulled the MCX box and turned out it was loaded with a 290 Apex map, no $hit, pretty bad, anyways maybe another thing to check. I've never had a Phazer does it use the same coil packs etc? Wiring? Stock injector? Just thinking out loud here. So it's running in the 13s for A/F when its stumbling? Might be electrical.
M5
