My 2003 land rover discovery 2 makes a grinding noise when i start the engine and when i press the gas pedal.what can it be?

Hi welcome main problems are the abs valves causing the 3 dash lights (search 3 amigos online) a really badly sited compressor can cause air suspension models to fail giving the bags a slow leak the V8 is a solid engine but can have radiator expansion tank and cap failures
the other issue is electrics windows and door looms are problematic

CHECK GROUND WIRES CHECK COIL IGNITION MODULE OR CRANKSHAFT POSITIONING SENSOR IF YOU HAVE ONE

sounds like a worn timing chain--getit fixed before u buy a new engine!

The discovery is full time 4wd, you can change between high and low ratio, it sounds like a broken transfer case.

my 2003 Land Rover did that while moving and I found out that it was a loose mud flap. If it does it while it is stopped it may the lifters in the engine.

The second cable should be for cruise control. Your problem sounds like either a vacuum leak (air entering the engine unmeasured by the air sensor), or fuel vapor in the fuel rail. A vacuum leak can be determined by spraying starting fluid at the air intake hoses, plenum,and connections while the engine is idyling and noting where the engine accelerates to determine where the vacuum is leaking (unmetered air is entering) from. Tighten or replace gasket,hose,seals etc. Bleed the air on the fuel rail if needed with care.

if it stopped working make sure your brake lights aren't on. If they are you have a bad brake switch (located under the brake pedal). It's easy to replace. If the lights are not on check the vacuum hose isn't split coming off the intake area. easy fix as well.

Yep, that's the engine!
Seriously though, is it a TD5 Diesel? Is it more of a squeal? If so, it'll be the exhaust manifold.

It sounds like there is a fault with the automatic transmission. you need to go to the dealer to plug in the tester and see what the problem is. All you can do is check the oil level, that is , if there is a dipstick and not a plug on the side of the transmission.

need to change a new pump.