The engine idles normally when in neutral (automatic transmission) When shifting into Drive, it speeds up a little, going about 10MPH with foot off the gas. Looking for advice.

 

Charles this is the wrong forum?
Maybe the mods can move your post?
.
.
.

 

You may need your TPS reset. It can only be performed by a Jag dealer or a device loaded with jag-specific software.

It’s plausible that you might only need a throttle body cleaning. It’s easy to do and cheap!

 

I thought that normal RPM in neutral was lower than in gear.
That's the way I remember it.

 

No.

In gear, warm, the RPMs should be at 580rpm.

In Neutral, or Park, the RPMs are around 700rpm.

I would take a few hours and remove the throttle body. You need a 10mm socket to remove the four bolts holding it on to the intake manifold. It looks like there should be a gasket at the metal to metal connection, I can assure you there isn't.

Watch for the small coolant hose connecting in and out of the underside of the throttle body. A golf tee works well to block it up. The rest is pretty straightforward. You'll be surprised at how much gunk you have on both sides of the butterfly. Carb cleaner and rags. Should take you two hours, all in. Three tops.