being a carb and disp guy a got a quick question. learned so much here about my 7.3 diesel here thought maybe you guys might know . worked on cars my whole life im 45 now so not a rookie i own a body shop and can build any thing . // 03 ranger 4.0 157 k on motor ran great but with that many miles thought need to change plugs and wires . pulled three on one side and changed plugs and wires changed the other side one week later i wasnt expecting to have to pull wheel and splash shield to gain access . im guessing the ecm adj voltage for the large gaps on the worn plugs and now have new ones set to spec .0063 thou. truck is acting like a bad fuel filter at speed get on it it stumbles seems to getting a little better but not fixed . my question is did the ecm or coil pack get damaged by running one side tight gaps and one side big like a 1/8 will it figure it out.im still just learning about computer controlled ing.to me feels just like a fuel filter but wife said happened that day i changed the one side. any help is appreciated.

 

Welcome to the Ranger/B-2 forum.

With that many miles on it, could be a number of things, as it's past due for a number of scheduled maintenance items, that might figure in on whats going on & we don't know where you are on all past & present due scheduled maintenance items. Like the fuel filter you mentioned, PCV valve & it's connecting rubber elbow that likes to dryrot & crack, causing an unmetered vacuum leak that'll mess with fuel trim, clogged air filter, dirty MAF sensor, or seeing as how your wife thinks it happened after you replaced the last set of plugs & wires, maybe revisit them to make sure they're fully seated, routed properly & the plugs in that bank didn't get damaged in the gapping, or installation, or you didn't accidently disconnect a vacuum line somewhere. Do you have a CEL lit, if so run this puppy by your favorite autoparts store for a no cost computer trouble code scan & post All code Numbers, as they can offer up good trouble shooting clues.

Our 4.0L has a waste spark ignition system, so it needs wires & plugs that'll be able to hold up to the double work load a waste spark system puts them through, as the plugs get fired on Every turn of the crankshaft. So I hope you opted for the specified OEM wires & fine wire iridium enhanced center electrode with platinum pad ground sidewire design plugs.

The finewire center iridium electrode plugs hold gap longer, but are easier to damage when gaping, as is the platinum pad on the sidewire, so we have to go slow, sneak up on the gap & not force the gauge through the gap so as not to damage the electrodes & a wire type gap gauge is recommended for gaping.

Also, did you pull the B- battery cable to wipe the computers KAM, so it could begin building new fuel trim tables after the repairs????

Some thoughts for pondering, let us know what you find.

 

thanks paw paw , i have done all maintenance since 10k mi if i remember ford recommended 100k fuel filter it was done at that mileage with a motorcraft . no running issues at that time just replaced for maintenance . i have all FORD parts in my trucks. no Chinese or Taiwan stuff for me!!!. . was careful when gapping didnt damage. ea one done separately and double checked before moving on to next one . all wires seated . new air filter /will check pcv and hose i think there are ok . it happened after i changed the first three on one side i started it but didnt test drive before she picked it up from my shop ran good just when getting on it when at speed 40-60 it missed like a cloged fuel filter or pump going south . but she said never felt before until i did the first three . i thought after i did the other three one week later it would be ok . it is still same and i didnt know how computer worked on this ing. no cel and i have a good snap on scanner that i was going to check fuel pressure while driving but havent yet. // what is waste spark system?? they were the motor craft plugs (platinum) and factory wires . do you think pulling the - batt cable might help im a old school mechanic and really dont like computers and sensors.feels like fuel to me but my gut tells me its something i did by changing the plugs i couldn't believe the gaps on the old plugs i wish i still had them here to measure at least 1/8 in but truck ran flawless . what does the ecm do with the voltage ? ill try to update as i find out whats up. thanks agian wes

 

why don't you try putting the old wires back on and see what happens. BTW that might be the best avatar I have ever seen.

 

Not sure what the 03 fuel filter replacement schedule is, but my 99 is 30K replacement.
Probably a good idea to check fuel pressure at the fuel rail schrader valve test port. I'd do a flow rate over time check also. A clogged fuel filter could cause delivery problems during acceleration. Your scantool should be able to shed some light on whats going on with long & short term fuel trim numbers also.

The computer doesn't change the coilpack output voltage, just adjusts timing, dwell ect, depending on inputs it get from various sensors.
Here is a spark plug mini tutorial that might be helpful in gitting a grip on our waste spark ignition system. https://www.ford-trucks.com/forums/1...l#post11067454.

An excessive spark gap with worn/rounded plug electrodes will in effect amount to a slightly retarded spark, as the coilpack will have to take a little longer time to build a higher voltage to cause the plugs to spark & yes your right, a wider gap makes it harder on the ignition system. My 99 4.0L has a .052-.056 inch spark gap spec. I usually set mine to min spec, as it'll make for faster winter starts, slightly advances the spark & as the gap is always opening up, the spark gap will stay in spec longer.

Good idea imo to stay with OEM parts, I do with most of my Fords also.

The computer controlled vehicles aren't so bad, once we get an idea how the system works.
Basically the computer has a number of sensors that give it info to help it make decisions about what to do about fuel trim, spark timing, how much EGR to feedabck, how much vapor recovery to feed the engine & what gear the auto tranny needs to be in.

Then it makes decisions to cause it's actuators to make split second decisions in adjusting spark timing, fuel injector squirt time, to try & keep the air/fuel ratio as close to Stoichiometric 14.7:1 as possible & when to shift the tranny. So if any of it's sensors are providing corrupt info to the computer, or if it's actuators are acting out, then the engine runs poorly & things act out.

The good thing is if the computer is monitoring the faulty circuit, it can self diagnose & turn the CEL on to tell us something hurts & the trouble codes it stores in memory provide good clues to which system has problems & what the problem in that system likely is, so it helps in trouble shooting a problem.

Yup the old carb & dizzy system was much simpler, but it couldn't make very accurate fuel trim or spark adjustments on the fly & sure couldn't self diagnose.

A dirty MAF sensor can also mess with fuel trim & cause accelleration problems, as it's sending the computer info on how much air the engine is taking in, so if the MAF sensor is dirty, it provides corrupt info to the computer & that'll cause the computer to mess up the fuel trim.

You could hook up your scan tool & go for a drive & see what kind of info it'll capture in its snapshot mode when it acts out, on things like fuel trim, O2 sensor output, MAF sensor readings, throttle position sensor input, engine temp, ect, ect.

 

Your gap you set them to is way off. Set it to 0.042.

 

His 03 4.0L owners manual has AGSF-34FP plugs specified on page 231 & a .052-.056 inch spark gap specified on page 238.
Dang I see the link times out!!!! So try this link from our "Tech Info" thread & enter your vehicles particulars to download or check the owners manual
EDIT: https://www.fleet.ford.com/maintenan...ls/default.asp

 

I can't access that link you provided, but FWIW, my Ford shop manual for my '04 shows a gap of .061 - .068.

 

sticker under hood said .061 - .068


thanks paw paw im gonna change fuel filter and get a manual. thanks wes

wires and plugs gone // thanks hard, not to stare at her wes

 

Go by the under hood sticker, rather than the owners manual figure, on spark plug gap.

 

Ok, it seems there are lots of conflicting information ont he gap, go by the one under the hood. However, you should set the gap to the minimum of 0.61, and not the maximum allowable gap. The idea is that the gap is in spec from the start, and as it wears and the gap widens over time, it stays in spec. If you gap is already .068, then if it wears at all, you are out of spec.

 

i forgot to update but fuel filter it was ! she runs good .i still double checked all wires . i ran my scanner first time on this truck! had a missfire code #5 cyl , probibbly from before work. nothing elese had this truck since 16k have 157k now so cleared the code and lettin her drive it

 

OK, good feedback on the acceleration problem being caused by the fuel filter.