My car hasn't been running in over a year (blown engine), but she's finally back. My car runs great while cruising/WOT but at idle it runs shitty especially when its colder out. Its been cold the last few days and it was idleing bad but today it was like 65 and it idled good until tonight when it got cold again. Ive checked tps, isc, boost leaks, timing. Also my boost guage reads like -15 when it idles bad but when idling good it was reading -18. Could this be a faulty AFM?? or something like a fuel pump.