rough idle
 

hey guys, im having a problem with my idle. When i come to a stop light it dips down real low, even with out applying the brakes. Sometimes it will circulate between 1000 and 500 rpms by its self. It allstarted when the car developed a miss. I thought the miss was a coil so i ordered the msd coils. That did nothing for the car it still missed, then i changed the plugs, in which case i had one come loose in the head and had to do a timesert. This cured the miss. From here it then seemed like i had a vacuum leak. I replaced all vacuum hoses. Still no improvement. The next thing i went to was the IAC, and to no avail still idiling weird. At a light it seems like the car has a miss, and it shakes the car a little, but when i give it some gas it is fine. There is no performance loss on the top end as i had enough to show a bullit who the boss was yesterday. so as i said the car has new plugs, new msd coils, all new vacuum hoses, and a new IAC. Im lost from here my only other thought are possibly a throttle positioning sensor of a fuel filter (Car has 98K). Thanks for the help guys

mine was doing that when its tps was about to go out. then it started to idle all over the place after a while. maybe thats it.

thanks man, that about all i have left to replace

bump, guys any more help