ok so i just got done changing the plugs on my 02 3.0. earlier this week i believe it developed a miss fire. one second it was fine then it jerked and and at idle it was rough. shut the truck off and turned it back on and it ran fine until the next day. it stated jerking again and rough idle when i was on the gas but more often then last time. it was throwing no codes what so ever. a day or two ago it was worse. rough idle all the time and the truck struggle about 3000 rpm like it just didnt want to go up higher. so i changed the plugs. Autolites and gaped them at .044. now its doing the same thing but a bit less. its got a rough idle at times and and at times it revs like normal. i pulled the power off the battery right now so i can reset the computer and see if that helps. if it doesnt were else should i look. its not throwing any codes right now so any help would be helpful.

 

its not the truck.. its the driver haha jk will

 

lol your probably right laz. truck has a bobo driver lol

 

Have your wires or fuel filter been changed recently?

 

no not wires thats my next go to thing.

the fuel filter was done... oh maybe a little over 10k ago if that.... im at 55K miles btw

 

Filter should be fine.

I dunno about Fords, but on Yotas you can check the resistance in the Wires via multimeter to see if they are still within spec.

I assume you can do this, if you have the specs to guage off of

 

thanks ill see if i can find the specs for it and check.

you think i should just go head and change the wires out anyway? just for preventive maintenance for the future

 

well i hooked the battery back up and let it idle for 15 min with and 15 min without a/c. now its just doing it randomly. will will idle just fine and then start wanting to not rev wants i press on the pedal. then at times it will drive like normal. anyone have any ideas? think maybe it could be a bad injector?

 

ok so it finally threw a code. P303 missfire on cyl #3. whats a way to check if its injector problem?

 

I bet one of your wires is loose on your coilpack. I had one jump off the other day on my 2003 2.3 and I knew right away thats what it was. I threw a p0302

just so you know, you should always check the gap on the plug before you put them in my plugs I recently replaced mine with were all way different and i fixed them all before putting them in.

 

It could be a loose wire,bad wire,or bad coil pack,ive had alot of problems like that with my 3.0.

 

ill go check it once the engine cools down enough.

i did check all the gaps. set them all to .044 before putting them in



EDIT: just went out and checked. all the plugs wires are tightly on and pushed in. any advice on the next line of action?


i should also add that the problem is now at idle and hesitates on taking off after being stopped through 1k-3k rpms usual normal driving

 

did you make sure that your wire's are going to the right plug? Sounds to me like some wire's got mixed up.....just re-verify you wire's are going to the correct plug. Also what did you gap your plugs at? What kind of plugs did you get. It is possible that one of your "NEW" plugs is actually bad...I've had that happen with autolite's and I pulled my hair out to figure it out.

 

They are stock wires which is what im thinking is going to be the next to change. once i pulled the plug and changed it i hooked the wire right back on it so they wouldnt get messed up. gapped them all at .044 and i got autolites. i was thinking the new plugs might have had a dud. how did you check for it?

 

i just had something similar and it turned out that it was a couple of wires had been dried up or something from the exuast manifold and developed bad spots so that when you bent it it would snap in half. i visually checked them but didn't notice it until i went to pull the wires off to do a compression test.

 

well what I did, which you can do to is hook your plug up to your lawnmower wire and pull the start rope, and ground the spark plug out...it should spark when you pull the rope. Some people do it on their truck, but I get nervous doing that. Maybe someone else will chime in....

 

I say try a new plug in that cylinder before you go chasing down any further problems.

 

ok guys thank you for you responses. at 3:30 im going to back to orillys to get my new Motorcraft wires. if that doesnt work ill try the #3 spark plug. is the #3 cylinder located passenger side next to the fire wall?

 

Water in the fuel will cause this same problem.Try some dry-gas through it.

 

welp i fixed it today. ended up needing new wires and a new coil pack. just a little tip to anyone who is changing there plugs... change your wires while your down there helps with alot of aggravation. thanks to all that put in advice. it was helpful