I had the crank position sensor replaced on my 2103 350 about 2 weeks ago. Not sure if there's a connection but since then, idle at cold start seems high (around 1800 RPM). Seems to me that on cold start before it would idle at around 1000-1100 for a 2 or 3 minutes and then settle down to 700 or so. Now, I notice the idle stays high for at least five minutes and that the tach swings 3-400 RPM when I first start driving at speed, especially when I let up off the accelerator until 15 minutes or so after start. I figure it can't be good for the engine to rev so high when initially started, and it's wasting gas too.

I've checked codes, and there none, but it just doesn't feel right. Anyone have any experience with this? Thanks!

 

I see you're in MD. I'm in NJ. I see the same behavior. It happens in the cold temperature primarily and I think it's pretty normal. I hover around 1.5K RPM and slowly go down to 1K to .75K RPM in about 2 minutes. During warmer weather, it starts off around 1200 or so.

 

mines is always high when the engine is cold. if you put ur car in park it will idle high but if you put in drive it will idle low when the engine is cold, so the engine can warm up faster

 

Thanks. It seems to me my highest idle before the sensor change a few weeks ago was around 1.1-1.2k too, all year; it is more like 1.5-1.6k now. No codes, and it settles down after 4-5 minutes, so I'll just have to get used to it (we'll see what happens when it gets warmer, too). Thanks!

 

What you are seeing is perfectly normal cold idle characteristics.

 

As others have stated its normal with the cold. Mine does it also.