My truck runs bad please help

It sounds to me like your exast manafold is loose or the gasket is blown. The backfire and pop is usually cold air getting in to your exost, It could also be blown head gasket or cracked head, as with both they will expand when hot and it will generaly get better. If thats the case it will only get worse. If you have white smoke coming out your exost when it is cold than it is a head gasket. Check your oil and make sure there is no bubbles (water) on dip stick, and no sluge in your antifreeze.I hope this helps. JACK

Well i really dont think that is the case it has to be something on the truck there for i have bought a new motor change it and still have the same thing going on i have changed the coil cap plugs wires 2 new heads on the last motor it runs real bad in the morring then the temp get to abought 170-180 then it's good to gotill the next day we have scaned it time and time over it wont read to my ECM no codes when i turn my key on there is no check eng light ummmmm.so if anyone has seen this please help then ill make a fat donation

DID YOU SWAP THE COMP TOO? SEEING AS ITS A NEW MOTOR FIND SOMEONE WITH A SCANNER THAT SHOWS HOW ALL THE GAGES ARE WORKING. THE CHECK ENGINE LIGHT WONT ALLWAYS GO ON IF THE SENSORS ARENT WORKING PROPERLY BUT THE SCANNER WILL SHOW HOW ALL THE SENSORS ARE WORKING. YOUCAN TELL BY THE CURANT FLUX YOUR COMP MITE JUST NEED A LITTLE REPROGRAMING. ESPESHALY IF THERES ANY HI PERFORMANCE UPGRADES I HOPE IVE BEEN HELPFULL

DID YOU CHECK THE COMPRESHON ON ALL PISTONS? COULD BE A BAD RING.

Ok now I have put two brand new heads all new gaskets and still pops and back fires out the tail pipe till the temp gets to about 180 then I turn it off for 5 minutes then it runs like new the rest of the day I am ready to put it in a grinder and call it scrap metal.