ok guys im posting this for my friend she aint to truck smart yet.....she has a 1998 f150 4.6 liter 4x4 and she just bought the truck and its been having heating issues first it was the blender door was cracked so that was fixed then the temp gauge would sky rocket......so we changed the thermostat.......drove it around all day today and it barely warmed up and now it wont heat at all and it wont start now .....any help would be great guys thanks

 

Well 1st off after changing the T-stat...you/she may still have some air pockets in the cooling system. So with engine cold, remove cooling system cap, making sure the heat is on in the cab, Park the truck on a incline & let Idle and come up to operating temp, hopefully this will "burb" out the air pockets. watch the purge tank level...so the coolant level doesn't get too low add as needed.

Secondly....if there is higher mileage on this truck...the water pump maybe not up to the task?

As to why it wont start?...how may miles did you put on with the no heat condition? I'm sure that you changed the fuel filter
make sure the fuel pump primes...and there is good fuel pressure...and there is spark. And checked the relay & fuses for ignition and fuel?

under cold run...it may have shifted to fuel and air ratio tables to full fuel and essentially its flooded .... if you feel that spark is good & everything else is in line.

Take the battery cable off for 10-15 min....this should reset everything. then try holding the throttle to the floor while turning it over....so its turn it over and then floor it...continue to turn it over...this should shut off the injectors and it should start. if everything is working correct

 

That covers a multitude of symptoms, none of which you provided. It could be anything from a dead battery to out of gas to flooded to whatever.

You will need to be specific.

 

Its got a full tank and a new battery

 

Seriously?

 

She didn't give me much to go on