Noticed a week or so ago it was idling funny sometimes...it revs up just a little & down. Then last night it start making a strange noise as well as kinda jerking when I tapped the breaks to slow down for curves etc. This morning it stalled once when I first put it in reverse so I put it back in park & restarted it...back out of driveway & stop at my mailbox. Before I could get back in it to drive off it killed again. What do you think the problem is & is it safe to drive for today until I can get it into shop to be repaired? It has a little less than 55,000 miles & was last serviced 10/10/12.