1994 Jeep Wrangler need advice

Just bought a 94 jeep wrangler, has been running good but all of a sudden it idled up to about 1500 rpm while in neutral then idled down, it now idles very roughly and unconsistantly and when I try to drive it will cut in and out and when coming to a stop from driving it will sometimes die, it is also blowing blue smoke from the exhaust, the check engine light is also on. Could it possibly be the 'throttle positioning sensor' or a bad fuel filter?