I am no mechanic so i'm thinking the worst. I replaced plugs, wires, cap, rotor and had injection flush done. Every now and then when i'm driving it will just make a loud pop noise from under the hood like its backfiring. Any help on what could be causing this would be nice. I have 104000 miles on truck. I just noticed right now that the vaccum hose to the cruise control is cracked, would this have anything to do with it?  

does it pop when you are moving the gas pedal toward the floor fast.. you might  have a lean backfire going on... do to a vacuum leak...  cracked air inlet hose...  blown gasket.. worn throttle position sensor...

you might also want to do a coil output test..... if you have multiple coils... be carefull..   most parts stores sell a under 10 buck tool that allow you to hook up a spark plug wire , the ground and crank the motor to see if it will throw a hot spark over about an inch... or 50KV...

even with an injector flush... a clogged injector may be causing an lean condition and a slow flame front that is still burning when the intake opens on the next cycle...

so many things it could be... without hands and ears on it...

a few more things... change your fuel filter....    if it is restricted... it can cause a lean  out also....    have a look at your fuel rail...  where is the pressure and the return line.. i have seen other jeeps with both on one end... this in my opinon could be the cause as there might be too much heat buildup in the fuel on the far end so it boils slightly.. this would spray a lean mix instead of a solid spray of fuel...
sort of a vapor lock situation... except without the lock...  

I will try to check everything today when it stops raining lol. It will pop anytime, it will even start idling real rough at idle and not want to move when i hit the gas. I thought it was the IacV but it wasn't. I forgot to ask, how much does it usually cost for a fuel pressure test?  

is the check engine light on??????
this will help diagnose some problems...


does it come on for 3 to 5 seconds when you start your truck????   that is the bulb test...   some people sell their cars that are broken by taking out the check engine light bulb...   if you don't know that it comes on for a bulb check when you start the car you might be buying a car that need $1K to 3K in repairs before it will pass smog... i see it all the time...

many times.... many many times...  it is loose ground wires....  dirty ground wires... dirty battery cables.... loose battery cables...

remember the computer system is grounded ONLY to the engine somewhere.. usually 2 or 3 wires... .  the battery is also grounded on the motor.. not always in the same place...      

if the computer is getting faulty grounds it will act bad just like you describe...  

light bulbs flicker if you only have them barely  plugged in... if the light cord is frayed or loose in the socket.. it will also flicker...

please see if you can get any codes out of the computer with a scanner before you unhook the battery.. or any ground wires...   the codes may be erased... and the car will fail many states smog tests for a few weeks afterwords..

code readers can be bought for under 40 bucks..

write the codes down ...  write the codes down... write the codes down.....  

I am hoping at this point the engine light will come on lol. I wanted to see if it would work so I unplugged the tps and engine light came on when i tried to start it. I will check the battery and clean it.. i never thought it mattered but the positve terminal is solid green stuff. at least i think it was green lol. Thanks for the advice, it's still raining here in Dallas so i gotta wait lol.  

The problem was fixed, it was some fault plug wires lol. Now to post my other question lol.