I have a 2001 5.4 liter V8 with 150K. It just started the other day with a sputter while idling, and a sluggish take off. So I changed the fuel filter. This did not fix it. However the check engine light has gone off. Now it seems more affected when its warm. Better in the morning in cooler weather. Highway speeds are hit or miss, and if I get on it there is no sputter or hesitation. Any one else ever have this? What is the next step? Thanks.

 

fuel pressure test. Clogged filters can kill your fuel pump. Thats why i change mine every fall..

 

If the CEL was on, there should be stored codes. Get them read. Autozone does it free.

 

Thanks. I was wondering if anyone could get the codes for me. I'll be heading there today.

 

The not so trained countertop mechanics at autozone told me one time when my uncle had a CEL that was on but had gone off, that if there is no actual CEL present, they cant pull the codes if there are any stored. Maybe theyre equipment? I dunno, I mentioned there should be stored codes and he said to me " If there is no light on, it wont detect anything" Or something like that.

 

If your Autozone is that lazy, just buy your own reader for about 35 bucks.

 

Im in the EXACT SAME BOAT right now, did you ever figure it out? Ive changed plugs (needed it anyway), some vacuum hoses, EGR valve, checked all of the vacuum parts that I can find, Fuel filter and still the same problem. I guess Ill be going to auto zone tomorrow to see what they say, but i suppose its narrowed down to a fuel injection problem unless a coil is going bad. I just dont think its a coil because every time one has gone out, it just went and a cylinder would constantly miss, not just at random like it is now.

 

I also have this same problem. I have changed fuel filter, plugs,plug wires, and even changed my fuel pump. I have no cel on and i have used a bunch of injector cleaner but the problem is still there.

 

i have the same problem with my 4.6. i changed the temp sensor, iac, cleaned the mas. it knocks and pings trying to accelerate. the idle is all over the board. stalls at stop lights unless you feather the gas

 

it sounds like you have carbon build up in the motor.

 

maybe it could be. it does have 236k on it. but why would the temperature matter then? it runs like a raped ape when it is cooler out and a pig when it is hot??

 

Could it be COPs? I JUST fixed a problem with mine where the car would surge/miss at idle as well as low acceleration and then at about 45-55 when I press the gas.

Changed the COPs which fixed the issue completely.

I'd also check your vacuum lines (EGR system, PCV system). Hoses are known for dry rot and develop holes which can cause similar symptoms.

 

cleaned the vac lines. don't have cop's did replace both coil packs

 

How old are the front oxygen sensors??

 

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