Hey guys, well as some of you may remember, a while back the truck was "jolting" and such any time i would give her gas.. finally after bout 2 weeks of this(and it getting progressivly worse) the CEL came on.. turned out to be a misfire on cylinder 4.. ok, did the motorcraft plugs/wires.. fixed it for about well, till now lol..

Its doing the same **** all over again.. just not as often.. but dam, sometiems its so bad, the whole damn truck will shake.. you can hear that the truck is running like ****..

NO CEL.. could it be the coil? Im really hoping its not a bad head.. dont want to know how much that will cost..

Oh, and i can usually tell how shes going to act when i turn her over.. i can tell by the sounds if shes going to run good or bad..

edit:

Shes got 83K on her..

 

maybe a spark plug..


my lady friends car threw a light and was misfiring on the 1st cylinder and it was a spark plug so thats my stab at it..

 

If wires fixed for a while. I would assume a bad connection somewhere coil related.

Pull your plug this will be the easiest way to see if you have a problem.

 

blhde - what do you mean pull the plug?

I just went to start her up, and she started pretty rough, when i put her into R, the whole damn truck started shaking, put her back into P, it smoothed out a little.. reved her up a few times, and she smoothed out to about where she should be.. Seems like the exhaust is quieter also.. may just be that im going def lol..

 

A recurring misfire on #4 cylinder in a 4.0 OHV can be caused by a slow coolant leak into the #4 intake port where the intake manifold meets the head. Replacing the gaskets often cures it.

 

hmm.. how would i check this?

 

also, is this hard and/or expensive to fix?

 

Pull the spark plug. If something is burning that shouldn't be it will show.

As far as cost its about 75 -80 bucks.


1999 FORD RANGER Intake Manifold Gasket

You need this gasket set and some black rtv.

Look for about 3 hours of shop rate, IIRC. About a day for a weekend warrior.

 

gotcha.. i checked the coolant.. THe radiator is FULL.. doesnt seem to be loosing any.. are there any other signs?

 

mine did that too. it was the egr valve. mine would idle rough and when driving at one speed it would jerk hard

 

do a cylinder leak test and compression test

 

most likely injectors check injector pulse i keep running into this on rangers at my shop theyll throw out a cel for misfire and the engine with shake pretty bad even worse with defrost or ac on.

 

It takes very little coolant loss to cause the #4 misfire, so checking the level may not tell you anything. Compare #4 plug to the others. After a while, the deposits (or lack of them) will look different if coolant is present.

 

hmmm.. i think i may take it down to the auto hobby shop and have them do a compression test.. how much do these usually run? or can i do this myself

 

a compression test is simply a matter of screwing a special gauge into the spark plug hole. With the coil pack disconnected, push down the accelerator and turn the engine over with the key about 5 times. Right down the number. Repeat on all 6 and compare the numbers. This will show a bad cylinder(s) but not what is wrong with it.

A leakdown test (different gauge) can pin point the problem. With it you go straight to the bad cylinder. In simple terms you are pumping air into the cylinder (through spark plug hole) while at top dead center. With the air in cylinder you can do some Sherlock Holmes investigations. Open the radiator cap. If the water is bubbling then air is leaking through the headgasket as bob stated. if air is leaking out the tailpipe you have an exhaust valve problem. If air is leaking out the throttle body, then intake valve problem. if air is leaking out the pcv hose at the valve cover, then you have worn out rings.

 

interesting.. this all seems pertty complicated lol.. well, not really , just i dont have the special gauges.. ill have to see what the shop will charge..

 

I was talking about a gasket leak where the intake manifold bolts to the head, not through the head gasket. A leak at the intake manifold gasket will not be detected during a leakdown or compression test.

A gasket leak into an intake runner or runners is a very common problem with 4.0L OHV Rangers. Vac leaks may affect any or all cylinders but a coolant leak usually affects #4 only.

 

yeah.. i dont know what it is or if its the # 4 cylinder that is misfiring again.. since there is no CE light yet.. all i know is yesterday she was running fine one minute, went into the BX, came out and she was running like ****! like anytime i would give her gas she would jolt.. put her in nuetral, and she would be fine.. rev her up in N, and fine.. put her in gear, and she would start to misfire..

 

ok, so today i realized that when the truck is 'jolting' or 'bucking' when i am giving the truck gas, if i let off or put it in Neutral its smooth.. could it be the tranny is low or something? i checked the tranny fluid and it was low, went and bought tranny fluid, checked it again before i added some and it was fine?

 

You need to check your tranny fluid when the engine is warm and its in park (or neutral for a manual).

 

yeah i did both times.. the first time i think i may have been on a slight incline.. And i hadnt drivin very far if at all, but reved the engine up.. the second time i had drivin for a few min..

 

it does sound like an egr problem. mine did almost the exact same thing. no CEL.

 

EGR problem.. so how did you fix it? did it like seriously shake when you gave her gas? like crazy shake? almost like it wasnt getting enough gas or air?

 

I had the same problem with my 2000 4.0. Replace plug 4 and runs fine for a while then it starts acting up then next is the cel light for cyl 4 missfire......I let it go and bye bye to the motor.

 

ok, so what was the prob. strakill? how do i fix it lol