Two weeks ago I posted a message saying my 91'740 auto seden jerks in a highway
trip. that day the car only jerks while it was climbing a hill.
but after that it seems disappeared..., I went for another 150 miles trip lately, but have not found the same problem.(anyway this time the road is better, not too many hills) but it seems the car still has problem,
sometime when I try to get out from a parking lot, especially when I put the
transmission into R, the car seems lose its power, and sometimes the RPM needle
can even jump to 1200 to 1500 when I reverse the car, and of course it is jerking at that time.
sometimes when I came to a stop sign, suddenly the noise of the engine increase a lot, and then it stopped, I have to restart it.

I do try to bring it to a mechanic, but the mechanic ask me bring the car in whenever the problem appears frequently.

so I have to asking for your guys help.

Thanks.