i have 95 k1500 305 5spd with tbi injection sometimes when i crank it will run then die and sometime die when putting in nuetral going down road i was told bad idle air control valve will this cause poor mileage its only getting around 12 mpg with stock tires it has new radiator water pump plugs wires cap just got timed it was 3 degrees off time and new bearings and front end parts uses no oil does smoke blacck sometimes also new coolant sensor has 227000 miles plz help

 

Put half a bottle of seafoam down the PCV valve hose
With the engine running, a bunch of white smoke will likely come out
The tail pipes. The more crap in your truck the more smoke.
Also for the next few fillups, pour a bottle of it into your tank.
It will help get rid of the moisture from all the ethonal and will
Also clean your injectors.

 

i have already did that it didnt help much in idleing now it wont stayying running when not having foot on gas but runs fine when pressing gas and driving down road

 

whens did you change the fuel filter last

 

with these FI systems it'd be something a sensor reader at a dealership or if you know someone with a plug in (not your cheap OBD readers, im talking about one of the $250+), they can tell you what all your sensors are reading at. clogged exhuast/fuel filter/air filter

 

i read the codes it didnt show any except 12 and got new fuel and air filter and got straight pipes wit no cats or muffler

 

it just dies when idlieng or idle below 500 sometimes it does it sometimes it dont

 

Idle should be at 650.
Maybe idle is too low?
Try changing fuel filter

 

I have the same truck and had the same problem and had been trying everything because i couldnt get any codes to pull up. One day my ses light came on n i ran it. idle air control, o2 sensor and both temp sensors