it sounds to me like your head gasket is bad like previously stated, when my 4.0 head gaskets were bad it would run but miss untill all of the water was burnt out of the cylinders.

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1993 Ford Ranger 4.0 5 Speed bw1354 manual Tcase swap 4in aluminum driveshaft 6in suspension lift 3in body 35 bfg km2's cragar soft 8s nite shaded tail 3rd brake light corner visor lights 2.5in flowmaster exhaust k&n filter hid headlights led lights everywhere warn hub conversion chopped antenna Kenwood deck pioneer speakers & 10in sub