Stumble/misfire

James86 · Dec 24, 2009

A few months back, my truck started shuddering badly and running rough. I immediately took it to my local mechanic and he said it was misfiring. Just from test driving it, he deduced the problem (bad injector) and replaced it. Fast forward to now, and every once in a while it does it again, but when the injector went out before, it just plain shuddered like hell and had no power, struggling to maintain 60 with overdrive off. But this time, while it feels similar, it isnt quite as severe, and its intermittent. It doesn't do it when I first fire it up for the day, rather, it seems that if I get it up to operating temp and park it to go inside for an hour, like shopping or visiting friends, then come back out, it'll run like crap. It's maddening becasue I don't get a CEL on misfires like my Cherokee would, and all the plugs and wires are less than a year old with less than 8,000miles on them, plus they're all snug and secure. One time when I threw in injector cleaner, it seemed problem free for about a week or so, but now it came back again last night. Any thoughts? It seems to me if it was another injector, it wouldnt magically fix itself like this. It's happened about 3-4 times in the last month or two and I've been writing it off to bad gas since I usually get my E-85 at the same station. This morning when I ran to the store and back, it was fine. I'm completely baffled. :icon_confused:

TomB1269 · Dec 24, 2009

Have you replaced the syncronizer shaft? It sounds as if your symptoms are; start it up cold and it runs fine (are you ever reaching max rpms 4500 or more) it warms up (you even let it heat soak) the start it up and all the sudden it mis-fires in the 3K rpm range or low 4k, and no CEL? sound about right? I had the same problem about 2 years ago after a plug change and a hot lap (pushing the truck hard, ie keeping it up in the 4k-5k range on a test run). The syncro shaft was me problem. I'll bet you get a intermittent whine as well it will come and go depending on heat level under the hood (hiway and stop cool - squeal, stop and go hot - no squeal). The reason there is no CEL for this problem is the ECM does not monitor the syncro for faults above 2500 rpm. There is a TSB about this and how to use the EGR circuit to test it.
PS: If you have this problem it is a time bomb. Eventually the shaft wables out enough to cause sensor to strike the wall (inside the black sensor) and the instant stop shears the gear at the cam and stops it from turning. On the bottom of this shaft is a rod turning your oil pump, and it stops too......New motor if that happens.

James86 · Dec 24, 2009

synchronizer shaft? whats that? ive never even heard of it before, but for the most part, you described my symptoms pretty well. as for a whine, i hear a slight one sometimes, but i kinda thought it sounded like engine whine in the stereo. i might have to a bit more hunting into this... my most severe shuddering was 1400-2000rpm range though, and when its shuddering, it idles around 600rpm in gear with the brake held. as its died once or twice when i started it, i suspected something with the IAC as well, but that may be related or not.

TomB1269 · Dec 24, 2009

Yup well known failure issue, the symptoms seem to vary. The syncro shaft is the rements of the distributor not that the engine uses coil packs & direct ignition. It is located on the left side of engine (passenger) on top of intake back by the heater / fan box. It is a round black plastic sensor with a short leg pointed at about 10 oclock as you look at it and is mounted with 2 screws thru the top. If you have it running and can place a hand on it you'll most likely feel it thumping/bumping. It should not have any vibration as it makes no contact with anything.
Check out these other post:
http://www.therangerstation.com/forums/showthread.php?t=32560

James86 · Dec 24, 2009

well, just got back from o'reilley's and ordered one for about 22 bucks. should be here saturday. at least its not too out of the way to get at. Im just hoping this will be the end of it as I saw that o'reilleys listed a shaft as well, but that was over 100 bucks. did you have to replace the shaft as well or just the sensor?

Ranger44 · Dec 24, 2009

Not to mention that the Sequential Fuel Injection on EEC-V is timed off that CMPS. Cam Position Sensor for the abbreviated illiterate.

James86 · Dec 24, 2009

well me and a friend went out and checked it and theres no vibration or anything felt thru the sensor, but i already orderred the part so i dont feel bad about making a 22 dollar gamble. i just hope its not the shaft as well, but if there is no vibration or anything id assume not. if so, how difficult is it replacing the shaft? isnt the oil pump at the other end?

James86 · Dec 26, 2009

well i have the sensor, but i found another threrad where it was mention ill need to replace the shaft and adjust the timing? i hope im not getting myself in over my head here.the other thread actually mentioned throwing codes as well:

1hot4D said:
ok, today i had a noise come from the back of my engine (2000 ranger 3.0 auto) it seemed to get a lil louder when you revved up then it went away. now the check engine light come one.

p0340 cam sensor

p1309 misfire monitor disabled

but the truck is running fine. thanks in advance

so is it possible that i bought a sensor for nothign and the SHAFT is what needs replacement? i really dont wanna tear into thia less than 8 hrs before i gotta be to work and i dont know a THING about the alignment/timing issue

James86 · Dec 26, 2009

ok, just changed out the sensor (not easy with a slight gut in the way) but anyhow, the shaft looked mint, and didnt seem to have any slop, and when i started it, it popped right off, idled smoothly at 1300rpm for about 25-30 seconds which i figured was normal since i havent drove it today, then settled to just over 1000rpm, with no squeaking or chirping, but then again it wasnt chirping in the first place. im pretty sure my synchro shaft is ok, and ive been hearing either vacuum, power steering or that pesky idler pulley, or any other myriad or rpm-dependent whines a cold engine makes. the noise is so subtle even when cold and ive never noticed it when warm.

Alex FX4 · Dec 27, 2009

Glad you got it fixed. does it change in tone or get louder when you turn the wheel? if so it power steering. If its the idler pulley, i fixed it by using heavy duty silicon lubricant and it stopped all noise from that. it can be bought at walmart and works well.

James86 · Dec 27, 2009

thats essentially what i used on the pulley as well. its a whitish stuff thats thicker than oil so it stays in there longer, but its fun trying to hit the innards of the pulley because of T/B and shit in the way. as far as the stumble, i thinks it might be a combination of things that worked against me like the sensor and cold winter air causing a richer charge with my CAI. i also have a hunch that there might be water or something in my ethanol since anyone who drinks liquor knows, water and alcohol mix whereas gas sits on top of water. anyone else here with a FFV notice shittier gas in winter?

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