Before i started to have problems i would notice the car would shake back and forth briefly usually on stop signs and lights and would become more frequent with time. It would sound like the idle doing it. Yesterday when i started it up it had trouble with its idle and eventually stalled at a stop sign. Today when i pulled into the drive and put it in park i noticed the idle starting surging from its usual 850-900 rpms to very low and would have trouble not stalling when in park. I turned it off but then had trouble starting it back up unless i gave it gas and would stall unless i kept the rpms up with my foot. I drove it around to see how it would run and it had no real problems driving and kept a normal idle until i put it in park and it started surging again. It seems every time it starts to have problems like the stalling i would hear a kind of rumbling or tapping coming from front. My mechanic said my 1998 v70 had a head put on and at start up would make a clicking noise because of it. Im not sure if its the same noise or not. the car has 102000 miles on it. Would the head have to do with anything? any help would be great.