If I let my truck set an extended period of time, it seems like when I start it, it runs on 4 cylinders like one bank is firing, what causes this, I run it up to 2k or so and it started running on all 8. my 318 in my car does the same thing.

67 Ply. Belvedere II 2dr Hardtop 73 Dodge Charger SE 440+6 727 Dana 60 4.10 78 Chrysler Cordoba 400-4 727 9 1/4 3.21 1999 Dodge Diesel 2500 QuadCab Longbox 2004 Dodge Durango HEMI Limited