I have a 1991 YJ with the 2.5. Motor has been rebuilt about 4000 miles ago. Since we put it in it has a rough idea, slight miss. Im not sure how it really ran before that because the motor had low compression and the exhaust was loud. I checked the codes tonight and it is 23 which is telling me Map sensor vacuum. I checked all the lines and I have no problem there. I also have found that when I disconnect the vacuum from the map sensor it seems to run better but I get the Check engine light on by doing this. Can the sensor being bad cause a rough idle. When the jeep is cold it seems to run better until it warms up.