Can anyone help me with this? My truck has started to stutter or buck when I appply the gas gradually. It first was doing only at highway speeds and now it does it even at slow speeds. The problem is that it only happens after I run it for a couple of days and if I let it sit for a few days it runs fine. Also the check engine light isn't on. My mechanic says that nothing is appearing up on the diagnostics either. He thought it might be the mass air flow so I replced it but it started doing it again after a couple of days.

 

My dad had those same symptoms with his 03 when a coil starting going bad.

 

How old are the spark plugs, and what shape are the wires in? COP's or coil packs might be bad also.

 

I'd bet money on one or more of the coilpacks being bad.

 

This happened to me after I rinsed the dust off my engine one evening. Let the vehicle sit overnight to evaporate the water. Turned out that my action caused 3 of the coils to get wet and go bad. This was at ~75k miles.

The first 2 coils to go bad were diagnosed the next day by the service technicial. The 3rd coil did not go bad until a week later.

 

If there is no code you may want to replace your fuel filter. I just had the same problem and the issue was fixed with a 19.00 fuel filter as opposed to spending 100.00+ on coils. May not be your issue, who knows.. Good luck. Sometimes the hardest fixes are the simplest ones.

 

Forget the fuel filter , helped for a day then started up again.

 

Would the dealer be able to tell from the diagnostic test if a coil is bad?

 

No one will till the actual cop goes bad. Just keep driving it and eventually it'll throw a code. It's a pain in the ***, but it's the only thing you can do other than going out and replacing all of them at once.

 

Check the iac (intake air control) valve. My truck did the same thing, put a new iac valve in for 60 bucks and ran like new!

 

Its 99.99% a COP.. had the same thing happen on my 02.. and since i just so happened to have 2 extra complete sets of COPS, i switched the entire set and the issue dissappeared.

 

I am having the same problem as of two days ago. It feels just like it did two months ago when I washed my engine (like an idiot) and toasted a couple COPs. I replaced all of them (and spark plugs) then with those cheapo Chinese ones on eBay as recommended here and it ran perfect up till now. Has anyone else had problems with those eBay COPs? It sucks because it's not throwing a code yet either (I have a couple spare known good ones...)

I see that these "guaranteed" COPs came from a store that no longer exists now. Are they all crap or does the 'other' store on eBay sell ones that actually last? (alanisdeals06)

I thought $65 for 8 was too good to be true. Is there a compromise to the $60 each factory ones?

Any comments would be appreciated.

 

in my experience and 4 years as a ford tech.. spend the money on the factory Cop's.. they are worth the money.