My wife has a 2006 jeep liberty, 3.7L engine, auto 4X4. Has 40,000 miles. The problem is suddenly started having a rough idle at start up, and then the check engine light came on. We had a parts store check the codes and it came up random misfire. The check engine light blinked once, pause then 4 times and stays on, which is supposed to be the map sensor. I changed the plugs (gapped to .040) and changed the map sensor. Unplugged the battery for 10 min. and it started out ok. Then it had the rough idle again and the check engine light stays on, and again the engine light shows map sensor. So, any suggestions as to what the problem is and a solution for it. Thanks.