F150 idling at 2200 RPM

[waxworm09]

I had the post last week about replacing my thermostat. When I replaced it the hose leaked almost a gallon of antifreeze on the motor. Ever since then, every time the truck warms up and I put in park, the rpms spike to around 2200. I put back in drive and it runs fine until I put it in park again. At first it only happened after driving the truck 20 minutes or more, but now the rpms stay way up there even when the motor is cool, problem seems to be getting worse. I'm sure something got wet from the antifreeze spill, anyone have any input as to what may be the problem? The truck drives fine its only high rpm in park and neutral. Hope I didn't damage something too expensive.

[Jeremy airjer W]

Vacuum leak?

[delcecchi]

Are there any vacuum hoses in the vicinity of the thermostat?

[Macgyver55]

Sounds like a vacuum leak to me too. Make sure the hoses going to the throttle body did not get pulled off or cracked when doing the stat. Did you take off the air intake tube or air cleaner housing when changing the stat? Make sure all the connections are tight and make sure the air cleaner cover is back together properly.

[waxworm09]

Well I'm hoping the hose was the issue. I fired up the truck, it jumped over 2000 rpm, shut it down and looked for a loose hose. I tugged on a hose nearby and it popped loose very easy. So I reconnected it, started the truck, and it idled at 700. Drove to town put in park and it jumped over 2000 again, drove home put in park and it idled normal. So it happened once after the loose connection, not sure if the problem is solved yet but its a lot better than it was yesterday and earlier today. Thanks for the input, and I'll check a little closer tomorrow morning to see if anything else might be loose. I did remove the air filter also to check it when I swapped the thermostat, I'll check that again tomorrow. Thanks again everyone for the input.