I have a ticking sound from the engine, it however doesnt sound like a valve or rocker. I believe it to be an injector or two. Is this common for injectors? My previous fuel injected vehicle was throttle body injected not direct injected. Is this a sign that the injectors are going bad?

I have never personally heard or heard of, fuel injectors ticking on a 4.0. Doesn't mean it doesn't happen. If, as you say, it's not an engine tick, it could be an exhaust leak.

I suppose it could be an exhaust leak but that is not what it really sounds like. It had a verh mechanical click sound to it.

X2
I would check for an exhaust leak

you should be able to feel a injector that is ticking that hard

just hold you finger on each injector you should feel the bad one

If you think you are hearing this clicking sound coming from the fuel injector area. Just think about what is right next to the Fuel injectors....The valves and lifters......both of which make a VERY distinct ticking sound when worn from high miles.

I havent taken the time to look for it, might do that this weekend while I am under the hood replacing the heater valve. I guess I will have to break out the "mechanics stethoscope"...commong known as a screw driver.

my a/c compressor ticks

No A/C so I can rule that out...but you might want to get that checked.

broke piston? thats what happened to me

I also am hearing this same sound. It gets louder and goes faster as I accelerate. How many miles does your motor have?

the exhaust leak does sound mechanical so it is deciving....it could also be a lifter....check your oil level if it is low add oil and see if the clicking goes away.

I agree with the exhaust leak,a leak at the union of the pipes echoes just like something bad.Sometimes you can't see the crack till it's off.
I have also read that these motors are known for piston slap.Haven't read enough to really go into it but it's something to check out.

that is most definately a crack in your exhuast manifold

i've never owned a 4.0 that didn't tick (or leak)..and yes injectors can produce an audible tick