hello everyone I have a 99 f150 5.4 4x4 xlt the truck dies at low speed and wont start back it several times to start, changed a lot parts and cant find the problem this what I DONE fuel pump, fuel filter,egr valve,iac valve,coil pack,spark plugs,clean the TB,anybody please help im desperate and dont want to spend more money i olready took it to a ford dealer and they just got my money

 

Check the fuel pressure when it wont start or dies. Check the fuel pump relay. Is the check engine light on?

 

we didnt have any pressure and we changed the fuel pump and no codes or lights on it dies went i drive at low speeds if i press the gas it stay on

 

Another thing to look at in the fuel system is the fuel pressure regulator and fuel pump relay. When you keep it running with your foot on the gas does it run ok? or still want to die?

What did the ford dealership say?

 

hi Toyz hope u keep helping me and thanks, i already changed the fuel pressure regulator the dealer first changed the DPFE sensor and nothing they charge like 450.00, i took it back and they say it was low on oil can u believed now the truck runs fine if i keep the gas press and one more thing if i turn it on and keep it on park it dies waiting 20 to 25 minutes it ran alright for a monht after changing the fuel regulator and the EGR valve but start all over again is there an easy way to chek the realey o i just get a new one

 

I don't know how to "test" the relay other than feeling if it is getting hot, which it shouldnt. If you can keep it going with your foot on the gas, it is probably not the relay. I would remove and inspect your IAC valve to make sure it is clean and working freely. Regardless that it is new. Not uncommon to get defective parts over the counter. What brand is it? You should also check the voltage at your TPS and make sure it is correct.

 

I will check the IAC it is from auto zone, i had the truk on and disconet the iac and didnt make a diference, now im doing the same with the tps sensor does this had to do any meaning o im total lost what has to be the right voltage on tps i did use a regular tester at the tps plug and it lights low i dont really know how to do it

 

hello everyone if somebody has the same problem try replacing the crankshaft sensor that really work for me good luck

 

I don't mean to sound diserspectfull but you going about this with no basis or proof and already spent a lot of money for no results by changing parts.
Unless you know how the systems work you will not know what is or is not a correct operation or response to what you do.
Start over again with the stall and begin to discern what the conditions are.
1. Are you able to prevent stall by keeping some throttle on?
2. Is restart difficult? If yes will it start with some throttle applied?
3. Does it cold start ok and go to high idle without your help with the throttle.
These operational answers are important to get a clue as to where to look for the issue and may lead to looking in other related areas depending on what you report with consideration of what already has been done.
Working on the EGR and other areas are not productive for a stall unless proven to be an area of concern.
Good luck.

DISREGUARD if you already found the issue according to your last post.
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