cliffs:
2003 3.0 120000miles
9/12 get a cel flashing , truck feels like its slightly misfiring only when at idle, five minutes later cel stops flashing and motor is back to normal no loss of power
11/12 cel returns with same conditions but is only when at idle again,throws code for cylinder 5 misfire still no loss of power like a misfire

-truck has new plugs wires and coil pack 6/11 about 25k on them now
-had cam pos. sensor and synch. replaced about 50 k ago
-fuel filter replaced 10k ago

i changed plug on cylinder 5 and new coil pack this made is better but still feels like a slight misfire/vibration,i take it to ford dealer they say they cant pin point it. would like to open top of engine for 1000$. engine never lost any power, no oil leaks , oil changed every 4k with full synthetic ,i drive it there and back home at 65 with no problems, no noise , nothing!

anyone have any ideas?

 

update :
clogged catalytic convertors! what a pain! magnaflow cats otw and a heavy top clean are under way also, threw in a tuner for some better mpg (19 atm)

 

odd enough

 

How did you determine that you had clogged cats? Just wondering because I'm having the same symptoms. Replaced coil pack and plugs yesterday and today so I cleared the check engine. Still has the same rough idle. Waiting for the check engine light to come back on so I can pull the code.

 

My 2002 just had the same issue over the weekend. I drove it yesterday on a 150mi round trip over to a friends house. Check engine light came on, and it felt like it had a major misfire. I let it get down to about a half a tank of gas, and I poured in half a bottle of sea-foam in the gas. Drove it a little harder on my way over to a friend house to borrow his scan tool to pull the codes. When I pulled into his driveway the check engine light turned off. He looked at it, and said it still had a sight misfire. Plug wires, and plugs are still originals. Drove it home the rest of the way (about 5-6 miles), and the check engine light never came back on, and it felt like it was running better. I'm still going to do plugs and wires before my trip down to the cities for Christmas.

 

After alot of reading, I'm pretty sure most of the rough idle and check engine light problems are from what they call valve recession. It is a very very common prob with the 3.0 v-6. My opinion is Ford should make this a recall, and they will not do it. They put crappy heads on from the factory and they know it, but wont back their product. The only way to really fix it is to replace the head that is messed up with a heavier and stronger head. A new aftermarket head with valves and springs. I'm about to do just that in two wks.
I will try to get the web site for you guys later. Those heads I'm talking about are $210 per head and you just send your old head back to them in the same box. Anyway if you are still driving with that rough idle just keep blipping the gas at stoplights. That usually keeps it from falling on its face when you take off.

 

That name of the place that builds and sells new heavier heads is Clearwater Cylinder
1-800-572-1963 They also sale their heads on E-bay

 

Actually Ford did have a recall on this... but it has since expired... Affected 2004 and newer models they claimed...

 

I wonder why I never heard that and weird that Ford did not send me a memo or anything. On two different occasions with two different shops (Ford was one of them)....we checked and guess what NO RECALL. It would've been covered if I had the ext warranty, but that has nothing to do with a recall. I don't think I would want the same alluminum foil heads that Ford put on there anyway. I'm pretty sure the same thing would happen again. They're just not good heads. You could go to any shop that does this kind of work, and I guarantee you they will tell you this is a common problem with the 3.0