ok guys, i had the dreaded rough idle. it started with really horrible idle when first started for about 5 minutes,then it would smooth out and id be able to drive it great for the rest of the day. then it started getting rough only when in park and neutral and when started. at this point, no codes would show up. so one day the check engine light comes on and my car goes to ***. it started stalling,and would shut off sometimes when turning it on.

i started getting error codes,from maf voltage too high/low, to engine coolant temp sensor, to o2 sensor, to idle control valve. replacing the maf,engine coolant sensor,o2 sensor didnt do a thing,and i still received the codes.

so i replaced the wiring harness. it was in horrible condition.

started her up,and low and behold, it seemed that did it. the codes were cleared, check engine light was off,it was no longer idling rough. took it for a spin and came back, park and neutral she was smooth.

so today i turn it on,again smooth, drive for about 45 minutes with no problems, then when i put it in park, ITS BACK, OH NO. idling up and down up and down, but the car doesnt seem like its going to turn off like in the past. the base idle is normal but shoots up high and comes back down to normal.

so i turn it off and immediately turn it on, its gone. go for a spin for 5 minutes, come back and park, still smooth.

im going nuts. if i didn't replace the parts myself it would have cost me $4000 at the dealership(thats what i was quoted when i took it in for diagnostics).

dealership charged me $250 to tell me that, and another $250 total i was charged at other mechanic shops who also tried to diagnose the problem and came up with nothing, except try changing maf and wiring harness.

any ideas?