Guys, today I started having an engine misfire once in overdrive and trying to accelerate gradually. The truck start bucking pretty good. I do not have a CEL lit and am wondering how I will find the problem without a wild goose chase. Any ideas and suggestions are greatly appreciated.

 

Ok, let's start with engine type, and go from there

 

x2

Just a few things off top of my head w/o knowing specifics.

Spark plugs, are the original ones still in the truck? Mileage?
Fuel filter, when has it been changed last?
Possibly bad gas. Did you buy from your normal filling station?

 

If you had a misfire the computer would throw a cel and tell you what cylinder it was. I have had a few

 

Check for DTC's. I had a P0175 code before without a CEL.

 

The truck has the 5.4 3v motor with 100,000 miles on it. I bought it used 2 years ago with 46k on it so I'm not sure if the plugs have been changed. The fuel filter was changed a few months ago and I did just buy gas from a different station since I was away from my regular stop.

 

Take it to an auto parts store like auto zone or oriellys, have them scan your truck for DTCs and report back.

 

CEL does not stay on. Only flashes when misfire. Brought it to AZ and they got nothing because the CEL was not lit.

 

I would start looking at the COP's and plugs. Been there, done that.
You are correct that a random misfire doe's not generate a readable DTC.

 

I would change plugs, they are 100k plugs but most everyone changes before. I would almost put money on it that your plugs never been changed. Do a search for 04-08 spark plugs here. You will find lots of reading. Dont know if your familiar with the plug issue for these trucks, but there two piece and some have problems breaking off in the head. It is a known problem and Ford charges more to extract them if THEY break one or all eight!

If your handy with a wrench then you can tackle the job yourself. Find the TSB and it will explain exactly how to do it to minimize breaking them. If you break one there are a few really good write-ups here on how to extract them.

 

Well finally! Yesterday I was driving around with a full tank of Chevron Supreme and some fuel injector clearner in the tank to see if maybe it was just some bad gas. I got the misfire and the CEL started to flash and then cleared. I remembered from discussions here, that this should leave a CODE and it did Po306 or cylinder 6 misfire. I ordered a new motorcraft coil from O'reilly's and it will be here first thing in the morning. I'm hoping this will solve the misfire for now. I am interested in replacing all the coils and installing the Granatelli coil connector kit with solid wire versus springs. Any thoughts on this setup. Oh and I'll get the plugs changed too. Thanks.

 

Well I would have moved that coil pack to a new cylinder and see if that pack is bad.

 

I agree on that. Check it first at another location. My 2006 XLT just got the #6 changed also. My wife has a 2002 Thunderbird that just turned 100k and we have already replaced 1, 2, 6, 8 coil packs. I bet the rest will be replaced in the next few months.

I would like to know if there is something we can do to minimize those coil packs bugging out on these trucks. I just put all Bosch Platinum 2s in my wife's Tbird. My son's Expedition also had 4 and 6 coil packs changed in the last couple of months. I am thinking of buying them by the gross.

 

Just to be certain, the number 6 cylinder is the second from the front on the driver's side?

 

Thats right