Head gasket, lower intake gasket, Or worst case scenario a craked head or lower intake manifold. My mechanic told me the 98-00 4.0 head gaskets and manifold gaskets fail easily especially if the motor ever overheated. One tell tell sign that this is a problem is if you have to keep refilling your radiator fluid. Itll be a slow leak so check it every couple of days......If this is the problem its cheaper to have the gasket replaced than to get a quote of 2500-3200 to get a rebuilt motor put in. When I had this problem I gave it a tune up and replaced the coil and threw all kinds of money at it. I only started getting codes towards the end of the motors life, codes like cylinder missfire over and over, emmisions control unresponsive ( wich was funny because Mine didnt have an egr), system too lean. As I just filled it with water and replaced plugs the #1 started to go. Dont mean to scare you but I would fork the cash to have it professionaly checked by a shop who is used to working with these motors.

 

hmmm.. well, there is no radiator fluid leak.. So that rules out head gasket, correct? Could it be something as symple as a dirty MAF?

 

I assume it could be possible if the air fuel ratio is off, wouldnt hurt to buy a can of M.A.F cleaner and give it a shot

 

Ok, so heres the newist deal.. The CEL FINALLY came on again today on the way to the auto hobby shop.. Misfire in #4.. just like before.. im going to try a coil pack first..

 

What do your plugs look like after they burn up. The condition of the plugs will give you a pretty good idea of whats going on. The only thing that could be wrong with the coil pack itself is that its arcing in cy 4 sending too high of a charge to the cy 4 plug wich I would think would be unlikely, generally speaking (but not 100% true) the coil pack works or it doesnt theres no inbetween. If the pack is causing problems but its still working then you would have an electrical issue somewhere else

 

Oh and keep an eye on your temp gauge. If it starts going up and down outta no were.....you have a problem with leaky coolant

 

Your coil pack is three independent double ended coils in one assembly. A coil pack failure that causes a misfire on #4 should equally affect #3.

Instead of throwing random expensive parts at it, I would concentrate on trying to locate the problem affecting cylinder #4.

Unseated spark plug boot?
Cracked spark plug insulator?
Clogged injector?
Leaking gasket where the intake manifold meets the head?

 

honestly i said it once before check injectors usually 80% of the time its that. the maf wont affect it that much to make it do this dont waste money on a coil pack cause its not gonna be a coil pack.

 

^^^ Im right behing them,

 

ok, so no coil pack...


Ill check the plug today while im at the shop and take pics for you all.. The temp gauge is fine.. doesnt move at all.. Coolant has been at the same level since it got here about 1500-2k miles ago..


ok, so if i am looking at the engine from the front of the truck, right(drivers side) of the engine has the 1,3,5(from front of vehicle back) cylinders, correct?
passangers side has 2,4,6?

 

probe the injectors you can get to or if you have a fancy scan tool like snap on modus then you can run a live data feed while its running and see what gong on with it.

 

If you have factory ignition wires, they should have cylinder numbers printed on them.

Front to back:

PS = 1, 2, 3
DS = 4, 5, 6

 

oh lol.. well the arnt 'factory', but they are motorcraft.. i didnt get the chance to look at it anyways, too busy working on the BL that i didnt get done lol.

 

Have you checked for vacuum leaks, fuel pressure, sometimes you will get a random or cylinder specific misfire from poor or low fuel pressure along with a vacuum leak check the large vacuum hose that comes off the passenger side just behind and below the throttle body. You have to move the top radiator hose to be able to see it.

 

no i have not.. Unfort. i am headed on a 10 day TDY tomorrow so i cannot do anything with it, so while its in the shop to finish the BL, im gunna have him check the engine out.. Hopefully he can figure it out/.

 

Good luck. Lets us know. Sorry I want much help