97 2.5 motor, I have replaced the crank position sensor and the map sensor and new plugs. It runs great ,drive about 30 minutes ,park and let it set 30 minutes. Get back in it and crank it up and it backfires through the tailpipe like you turned the key off and then back on. It smells rich at the tailpipe and does not want to idle. Smoothed out a little ,drove it back home and it still idles rough and smells rich. Let it cool off for 30 minutes and it runs smooth again. I do not have any engine codes, I have a code reader. Any ideas obout what to look at next. I thought about trying a coil.