Why do my truck runs for 20mins and shuts off?

this is a TBI (throttle body injection?) or a quattra-jet?,,,changing the electric pump back to the cam operated pump (not even sure there's a lobe for this yet?)~

I really don't no I had sombody do the job. But I have had people tell me that the brain box nerd to be changed and I don't no if they done that are not

They said they had to put a elec fuel pump on it

okay this is quickly becoming a "franken-car" right in time for halloween~ seriously, let's break it down....used to have a heat riser and "stove kit" and piping from the exhaust manifold...all this Jazz has been replaced by the IAT sensor and the engine temperature sensor....are you with me? the computer needs to know how to enrichen the mix under ambient conditions and under operating conditions..check for the IAT sensor...buggers not even plugged in, I guess~

block temperature is a killer if not right~ okay every modern car computer needs to know how rich it is and how rich to make it...even after the fact with the 02 sensor and MAF sensor to find minute amounts of NO2 and CO (carbon monoxide) deadly...good thing we've got a catalytic converter to switch CO to CO2 and water vapor~....and NO2~

the basics, air, fuel, spark, timing, valve timing and ignition timing....you still with me?

also the battery should not be five years old yet as the new tin/antimony alloy batteries stop taking a charge gradually up to ten years....dead after ten....won't charge up anymore~

...also the Negative battery cable is connected to the frame/chassis thru one bolt only....much importance on one connection...take it off and with a coarse wirebrush establish the high-amperage connection needed....here and at the motor block where the 1/0 battery connection is~

Thanks I dont no anything about all of that dont even no where to start looking but I wanted to know what could cause this. I plan on taking it back to them as soon as I get a chance but can you tell me where those sensors may be located?. Thanks again

Thanks I also noticed that I have to jump it off to get it started

the block temperature is mid-court on the engine...where the flow of coolant might pass...the IAT sensor is on the intake plenum...snaps right in or out...a silly play-time for children replacement~

you could google both these items installation "images" to see what it is~

1/0 awg Wire is that big fatty red hard to bend triple nine conductor for the starter to get the POWER to turn the starter motor around~ http://en.wikipedia.org/wiki/American_wire_gauge

the reason you need a jump is because the GROUND power cannot get thru the frame/chassis...which is where I suggested that you wirebrush that place where the lug bolts to and the lug itself with a coarse wirebrush...maybe you will not need a jumpstart...maybe YOUR battery is not five yet and still okay....just cannot deal with corroded ground...got me?~

...also the 1/0 battery ground to the MOTOR block, usually located near the alternator.....wirebrush that one too...for good measure~

what we're trying to do here is make sure that your startermotor sees all that is available to start the car with...kickin' it round and round much faster, with POWER to the ignition and fuel pump to do their jobs properly....not marginally~

Thanks I will do this first thing in the morning you have been a big help thank you. I will let you know the out come