I have a new to me 1994 Jeep Wrangler 2.5 with 200,000 miles all stock. I bought it from the original owner who had never even put in into four wheel drive for $1200. It wasn’t running when I bought it and had been sitting for about two years. So far I have replaced the radiator with all hoses, basic tune up stuff and also the thermostat which wasn’t working after I got it going. It’s running now however not very well. It has some kind of idling problem which is making in run rough on and off. When its idling rough there is a good amount of smoke coming out the back then after about 20 seconds it stops and runs fine. Any ideas on where to start would be greatly appreciated.