2004 Land Rover Discovery II 4.6 122k miles

Rough Idle: Ive posted a few weeks ago about the rough idle and had no luck. The LR idles rough and ive replaced spark plugs, wires, coil packs. Ive also replaced the thermostat, flushed radiator, new coolant, greased ujoints, oil changed. Today I cleaned the throttle body..not sure what else to do to get rid of the rough idle.

High Coolant: Today I had the OBD reader hooked up while I was driving and the coolant temps were ranging around 215 going down the road and stayed around 221 when idle. I thought for sure the new thermostat and coolant would help this problem. According to other forums those temps are too high..any advice what I should check out next?

 

I'm assuming you have no codes stored? I say this cos you had an OBD reader attached so would have read them.

I would say those temps are a worry. System defo bled properly. No air locks?

 

Check engine light went away after replacing spark plugs. They were all misfire codes. When first starting and accelerating harder I do hear water noises under dash..possibly air in the system?

 

^Yes, you have air in heater core, if engine is hot park the truck somehow with nose up overnight, that will get rid of some air in heater core as it cools down, then with engine stone cold (keeping truck at same nose up position) raise coolant reservoir fill it up & open bleed screw & let it bleed out until no more air comes out, you may have to repeat this process a few times to get rid of all trapped air, (no more waterfall noise from under dash),
Some ppl get better results with fewer tries than others, (doing this has worked for me every time)

 

Try disconnect you idle control sensor