For the past 2500 miles, I have been dealing with what I think is water in my fuel. I have put two new fuel filters on, run three tanks of fuel drier through it and two tanks topped off with a can of 44K fuel system cleaner ($22 ea at the dealer). The only time it runs consistently well is when one of those $22 cans of 44K is in a tank of 89 BP gas. 89 gas alone--runs rough.

Although no codes have bet set, the 5.4 in my FX4 seams to be out of time. Is this possible? If the darn thing had a distributor on it, I would swear someone had turned it for me.

I bouth the truck used. Could the previous owner have reprogrammed the computer to only be "happy" with high octane fuel? The truck only has 38K on it, 'shouldn't be acting like this already--if ever.

I have had ii at the dealer (before the warranty ran out) and they pulled no codes.

I pulled the coil pack wires off one at a time and the change in the idle was the same with each.

Is there anything in the 44K fuel system cleaner that would raise the effective octane rating of my fuel to support my timing theory?-It runs great when that stuff is in the tank, but I can't afford to keep paying $55 for a tank of fuel.

Also, and this is important--If I pull a coil wire or fuel injector wire off while the truck is running, should a code be thrown? If so, something is wrong. Through all of the testing, no CEL has shown up.

Thanks for the help,

Sidewinder

 

Check the Idle Air solenoid (IAC) on the back near the firewall.Sometimes they get nasty and the idle becomes real rough

 

Thanks for the reply.

But my problem isn't really noticeable at idle speed. It shows up as a drastic loss of power in the 1000 to 2200 RPM range. The least little press of the pedal in OD kicks it back to drive.

thanks

 

For what it's worth....

A previous Expy 5.4L did the same thing and I too added the dry gas etc. It turned out to be a bad coil brought on by leaking antifreeze from heater hose.

It would only do it at a certain RPM really bad. It didn't idle toobad though. It was most noticeable at light or moderate acceleration.

Hope this helps---Bob

 

I've been looking for the "tell tale drips" from the AC line above #4--dry as a bone. It does act sort of like a COP flaking out, but no codes--not even when I pull the wire off while it's running. Why would it run consistently well only when the 44K is in the tank--I'm stumped and without any codes to read the dealers don't have a clue

 

if the previous owner put a new 'power' chip in, it would reprogram it to run on higher octane fuel

 

No such luck...I was looking for one of those so I could unplug it and see what happened. The only thing I see in the socket looks like a plug or cap with the computer code and a Ford part number (I think) on it.

 

I had something similiar. It turned out to be a crack in the porcelian on the #4 plug.

Still fighting some other things but it has power all around now.

It does like to ping.

tom

 

Even with 87 gas, I don't have any problem with pinging. I may have to break down and put a set of plugs in the darn thing. Man I dread that. I was hoping to get to the "FORD=Recommended" 100K before having to do that.

Any other Ideas Guys?

 

Have you replaced PCV, my pcv was defective. It caused hissing noise along with little rough idle condition, all of which is caused be build up in HCO. Once I replaced it, it was night and day difference. No more hissing, no rough idle. In fact, my baby idles like a little kitten (no engine-running noise in the cab). I couldn't believe this little $2.50 piece did the trick. Anyway, that's my 2-cent.

 

Y2KWHT150,

No, I have not replaced the PCV Valve. but when I unplug it from the valve cover, the idle does change. My problem is really not with the idle, it's a loss of power from 1000-2200 RPM--right where you need it. I think I might have a bad injector on #4. Maybe the 44K lubricates it in some way to make it work correctly, but when the 44K is not in there, that RPM range sucks.

Still working on it,

Sidewinder

 

Have you checked your primary and secondary resistance on COP's? If not, do so, that will tell if your COP is going bad.

 

How do you do that? I have been looking for a Caynes or Chiltons maual for my truck, but none of the auto parts stores in my area have one for an '02 yet.

Thanks,

Sidewinder

 

Haynes--not Caynes.. You guys know what I mean (must learn to look at the screen-not the keyboard while typing)

 

Sound like you have a nice problem.. Have you tried 93 or 95 octane to see if that has the same effect as the additive?
You may even find 101 octane at some places..

Here are a few wild ideas to run by the fuel injection experts..

If there is a knock sensor it is being to sensitive and telling the computer to pull too much timeing. The higher octane keeps the engine "quiter" allowing the overactive knock sensor from acting up..

The incoming air temp sensor is telling the computer that it is hotter than it really is.. resulting in the computer pulling the timing.

Did your problem just start? 2500 miles ago .. or has it done it since you bought it?