No throddle response when engine is warm then dies
 

Been stranded the last two days in a row, any help or experience with this issue would be greatly helpful.

After engine is warm, driving low speeds stop and go, the engine has no throddle response from being stopped. rough idle then i hear a few knocks from the engine compartment. From here sometimes the engine will finally run and sometimes it will just die on me and will not start until engine is cool. No problems while highway driving. Have fuel pressure at the filter (Cant find my fuel pressure gague to check the rail pressure) and spark on my coils.. Went ahead and replaced the fuel filter drove around 100 miles today and it died on me again at a stop sign. No check engine light so im assuming there is no code?

2000 F-150
5.4 engine
252,000 miles
OEM becides K&N Induction system

It's gotta be throwing a code, do you know what it is?

No check engine light so im assuming there is no code? Thats what they always say at autozone anyways. may need a nicer scanner to pick up codes.. Im at work tonight im going to run out and clean my MAF with some contact cleaner and give my exaust a once over. i seriously doubt its the MAF Ive seen similar post with my problem but never a good fix for any!! :(

Next time it dies on you look under the truck and see if the cats are glowing. What kind of temps is it running?
I'm just poking in the dark here, can ya tell?

I CAN tell, But definately worth checking out... Just looked under the truck found the Left Forward O2 Sensor had 2 chaffed wires, Looks like its been that way for a while. One wire is only hanging on by a few threads and dirt ect between the wires. the other is just minor insulation chafing... Hope it didnt ruin a cat. what do you think? Seems like I would have got a check engine light for a bad O2 sensor, no?

Turn your key to run. Check for CEL, if you don't have one, check the fuse or bulb. O2 wires are sensitive, - they can and triggered fault (CEL) from chaffing alone. Two whites are your heaters, grey is PCM ground, black is signal.

Yes check engine light(CEL lol had to google that one) comes on when key is turned to on. The white wire is the one chafed the worse it is only hanging on by a few strands of wire. It will be in at autozone around lunch so I will have it on this afternoon. Still not confident that's my problem since it never gave me a check engine light. Thanks

About the same issues my truck had last year, turned out being a bad intake gasket set. Was losing throttle and idled like a b*tch until warmed up.

Mine idles fine when cold and fine when warm only half the time. My problem is after engine is warm and either coasting to stop or accelerating from a stop rough idle a few knocking sounds from engine compartment I'm assuming it's coming through the induction system. Then it either dies out on me and will not start again until cool. Or after the hiccup it will run fine for a while.

This is why Ford made the use of a Scanner to look at the operating conditions in the program in depth and detect those out of limits.
If you can't see any codes there is little help but guessing, we can give you here.

I hear ya, thanks for your help. I replaced the o2 sensor today and about 30 mins ago got a check engine light stopped at autozone and it latched an o2 sensor fault. Lol go figure. Well cleared that fault, we will see if it comes back. I've pretty much decided if the truck dies on me again I'm gonna break down and take it to the dealership. I came across my fuel pressure gauge today its at 38 psi after turning the key off and on about 4 times. Keeping the gauge and a hammer in the truck so I can check pressure at the rail when it acts up again. And the hammer to rap on the idle control valve also dubs as a way to vent my anger and frustration lol.

I'll keep updated if I do so we can atleast identify these symptoms to a solution. Thanks for everyones help and if anyone has seen this I'm always open for advice.

Im leaning towards the cat... I had a car do that. Never glowed or anything, but after it was running for a little while, it would bog hard, piss poor throttle. I just drilled holes in the cat until I could throw a piece of test pipe in there.


-Matt

It seriously wouldn't surprise me if the cat is bad. Specially after seeing chafed wires on my O2 sensor. I will definately keep everyone updated.

Usually a bad cat will set a code saying the rear sensor is not detecting the oxygen levels it needs to see.
The PCM keeps track of the switch ratio between the front and rear as a means of detecting a bad cat.
A way to test for a plugged cat is by welding a small nut to the pipe ahead of the front cat that will accept a fitting and metal tube attached to a vacuum gage after drilling a hole in the nut center.
Most vacuum gages will register a small amount of positive pressure.
If the pressure goes much more than 2 psi with the engine at a low to med RPM, the cat is suspect.
If not, just put a plug in the nut and leave it in place.
Better to know before spending big money on a cat, just hopeing.
Good luck.

Very good Idea Bluegrass, wished I had access to a welder. Well I replaced the left FWD O2 sensor and started getting check engine lights.. turned out to be bad from autozone so I put a new one on. drove in to work 26 miles and no CEL's as of yet and No Hiccups with my engine so far. I hate that it is so intermittent those are the worst kind.