well i have noticed that my 04 f150 supercrew 5.4 has a hesitation in it from time to time and today my wife calls me and tells me that the truck dies on her when she stops at a light or spot sign. it di it to her twice. i asked her if the air was on and she did have it on. i told her to shut the air off and it didnt die in her again. at first i was going to blame the hesitation on bad fuel but now imm thinking there is something else. any sugestions?

 

how many miles on truck? if it only does it with the air conditioning on it might need a tune up, as the a/c puts an extra load on the motor that can cause hesitation and stalling

 

The computer may need to be reflashed by dealer, it supposed to raise idle speed to compensate for when AC is on.

 

check the EGR valve. My old truck would shudder at times then sometimes die. Wouldnt throw a code for the longest time. Finally it did. EGR Valve. Problem solved

 

Go to your local autozone, oreilly's, what-have-you and get the dtc's pulled and see what you get. While there, check your air filter. Buy a new one if needed. If you've got more than 20K miles on your current fuel filter pick one of those up as well. That will take care of the obvious stuff. EGR could be the culprit as well. I haven't heard a whole lot of EGR problems on this generation of rig but, my '02 mustang GT had the same symptoms and it was known to be an EGR problem on those 4.6L engines.

 

the hesitation happens when the air is off as well as it does when its on. the truck has 63000miles on it and as far as the air and fuel filter im not sure how old they are since i have only owned the truck for a month. i do know the air filter is a k&n so i will clean and recharge. i ran the air over the weekend while traveling and pulling my camper and ther was no problems. the hesitation was there 2 weeks ago acording to my wife.

 

well my wife called me at work to tell me that the truck was still dying when she stops. so i told her to unplug the brake box and it didnt die on her again. the hesitation is still there so im going to change the fuel filter. why would the brake box do that? it didnt do it when i pulled the camper last weekend. i baught the brake box and harness. i pluged it in and it worked. i didnt use the factory harness and relay is the a problem?