Hi all,
I have a question for you, I have a 98 ranger, 4x4 with a 4.0 v6, It started missing out at idle speed about 8,000 miles ago, i replaced the plugs, wires, air filter and fuel filter on it, seemed to help for a bit, it has now just turned 100,000 miles, and it is missing out at idle and running speeds, it will smooth out as long as you are not accelerating. the check engine light has came on, I took it to Auto Zone an had them do a diagnostic on the pc, an they said it showed problem on the #3 cylinder, the guy was in a hurry an very rude, so i didn't ask him a whole lot. Does anyone have any suggestion's on what i should do ? Any help would be greatly appreciated. Thank you Bill

 

Listen to that injector with a stethoscope or a screwdriver up to your ear. See if it sounds the same as the others, It might not be opening and you are running lean in that cylinder! Have you cleaned the MAF lately? That will help the idle quality and mileage!

 

I'd also pull the plug & plug wire & inspect them closely.

I pulled & gapped my 99's plugs when new, to the low side of spec & just pulled & checked them at 54K & found them to be .008" over max gap. So no way would they have made it to 100K & been anywhere near in spec. for gap.

So if your plugs are OEM, & you haven't serviced them, the gap is likely out of spec WIDE & that can cause a misfire under load.

Most folks replace things like plugs, wires & O2 sensors at 100K miles. Cleaning the MAF sensor, as has been suggested, probably wouldn't be a bad idea either.

If you decide to do so, be sure to remove it use & use a non residual spray, thats formulated for cleaning MAF sensors.

Let us know what you find.

 

Thank's for the info. I pulled out my #3 plug and it was all corroded up at the treaded area, do you guy's think i may hasve a leaking headgasket ? As i mentioned i replaced my plug's aound 8,000 mile's ago. I haven't checked the other ones. I have been losing coolant, a little bit at a time the oil look's ok, but in the coolant reservoir, there look's to be oil or something mixed with it. Any thought's ?? Thank's
Bill

 

That injector isn't feeding fuel for some reason(did you listen to it?) Is the electrode all black or is it normal? If it's black that cylinder isn't burning any fuel, the oil is just getting on it and not getting burnt off(yes all motors let some oil past rings and valve seats) Do you have an auto trans? Did you put anti sieze on the plug threads when you changed them?

 

Thank's Bluebeast, yes the plug was all black, and yes i have an auto. tranny. i\I am not sure what to listen for ?? And how do i do it with a screwdriver ?? I don't have a stethoscope. Thank's again

 

Have a used oil analysis done. Inexpensive and easy to do.

http://www.blackstone-labs.com/gas_engines.html

If it is confirmed that there is coolant in the oil, then you are looking at one of the following problems:

1. Bad lower intake gasket;

2. Bad headgasket(s);

3. Cracked head(s).

 

Thank's to all that helped me out, turn's out you were right paw paw, I replaced my plug's an it is running fine now, wonder why they never lasted very long ?? Only had around 10,000 miles on them, any thought's ?

 

OK, good feedback & to hear you finally ran this one down & seem to have put things right.

What brand & what kind of plug did you use???? Were they non platinum, or single platinum type?????

To avoid excessive electrode wear, we need to use double platinum plugs, of the proper heat range, in our "waste spark" ignition system.

There are only 3 coils to fire all six spark plugs, in this waste spark, coil pack system.

So each plug is sparked twice per cycle, once on it's power stroke & again on it's exhaust stroke (They are worked/sparked twice as often as a single coil ignition system.

They are paired together, (1&5, 2&6, 3&4) so when one is firing on its power stroke, it's coil companion plug is firing on it's exhaust stroke, then things reverse & the plug is fired on it's exhaust stoke, while it's coil companion is fird on it's power stroke.

Also in this system, half the plugs (4-5-6) have a reverse polarity spark, that emanates from the ground electrode. The other 3 plugs (1-2-3) have normal spark polarity, which emanates from the center electrode.

We should replace the OEM plugs with double platinum electrode plugs, as both electrodes then have platinum on them, to reduce electrode wear from the extra sparking & it won't matter which cylinder they go into, as both have platinum on them.

So if you used non, or single platinum plugs, the electrode wear will be much faster. Heat range & electrode metal type is important too, as it can cause exessive electrode wear.