Surge on acceleration

2000 stratus, 120,000 miles. 2.4L / feels like a misfire, when used scan tool found code for a random misfire. Intermitent surge when accelerating and there are days that it's really bad and engine looses power. Many shops said that there is no problem because it's intermitent, but now it happens all the time and the check engine lite si off at this time. Also yesterday it wont go any faster than 30 miles per hour and it gets up to second gear and speedometer went dead.