have a 99 by 4.6! First off when I start it it jumps to about 1500rpm then creeps down to 1000 and just hangs there. I put a new iac on and nothing. Second, while I'm driving around 40 mph my card starts vibrating I can feel it in the dash almost like its shuddering. If I floor it, I wants to go but it just kinda hesitates and stumbles so full power isn't there. I sometimes can smell gas as well. If I rev it, I sounds nice but sometimes it will bog for like 1/2 a second then rev up. i need help please! i have new plugs, I also have new radiator due to the oil trans cool breaking. Please any advice is great!