Idles low in park, high in gear
 

Hello everyone,

I've got a 2005 Mercury Grand Marquis with about 95,000 miles and I've got a question. The car has a weird idle... It idles higher in gear than it does in park. I don't know how much higher but I'd say about a couple hundred rpms more based on my hearing. Normally it would be the other way around, for example my Oldsmobile idles 800 in park and 600 in gear. Is this normal for the Grand Marquis? To my understanding the 05 doesn't have an IAC, I've cleaned the MAF sensor, replaced the air filter, checked the vacuum lines what else could it be?