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boomer
Dodge Dakota
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1/23/2007
08:21:44
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 Subject: Multiple Cylinder Misfires
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I had a check engine light come on a while ago. It comes on for a few days, goes off, then comes back on after another day or two. well, I had the code checked at autozone and the dude said it read "Multiple Cylinder Misfires." Every now and then the truck will idle a little rough but nothing horrible, most of the time its smooth. A couple of times when the engine light was off and I was accelerating it would miss a little and run like crap then the light would come on.
So my question is, what the hell can this be from? None of my wires are arching, I've had that problem before. I put a new cap and rotor on about a year ago. Is it possible moisture is getting in there? I don't think I got brass contacts but the next cap and rotor will have them. Any other possible reasons why this is happening? I have the stock recommended champion copper plugs, but I will be switching to NGK plugs soon. I'm also going to change out the crappy boshe O2 sensors with the NGK OEM sensors. I have no cat right now, maybe that has a little to do with it. Could it possibly be a different sensor? Like the MAP sensor or something? Or a dirty throttle body? Sorry for the unorthadox questions, thanks for any help.
'98 3.9L slt clubcab
K&N cold air intake
JBA headers
2.5" exhaust to flowmaster 40 series delta flow
7.5mm wires
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boomer
Dodge Dakota
JOIN HERE
1/23/2007
08:43:05
|  RE: Multiple Cylinder Misfires
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I just read a post and remembered something...I'm almost 100% positive my timing chain is making noise. I'm at least the 3rd owner and somehow I doubt it's ever been changed or had a tensioner installed on it. Is it possible this is causing my misfires? The noise is annoying enough, but if it's causing performance issues then I'm getting this done ASAP.
oh, by the way, my truck has 126k on it.
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boomer
Dodge Dakota
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1/24/2007
22:59:52
| RE: Multiple Cylinder Misfires
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I had a giftcard for autozone so I went and got a new TPS. I searched thru some old post about cylinder misfires and a couple dudes said they replaced the throttle position sensor and it was fine after that, SO hopefully this is all this is. I notice no one else has this problem right now. if the sensor fixes it, at least you will know what to do when it does happen. no responses yet for this at all. I'm honestly shocked!
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Mike Stager
Dodge Dakota
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1/24/2007
23:52:03
| RE: Multiple Cylinder Misfires
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Well, with the light coming on and going off, it could be something that is coming in and out of sensor range. I had a knock sensor that would set off the light if I floored my GMC van for a hard run onto the freeway. The engine was loose so the sensor would pick up the rod knock and set off the CEL, then go away once I was up to speed and took the strain off the engine.
If it's been running fine, I'd check the usual suspects ( wires, cap and rotor ), then go from there. Could be something simple ( most likely ).
Could be temp related too. What's the temp like in your area when this has happened?
My truck has been running poorly since the temps dropped below freezing.
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OBIO3
Dodge Dakota
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1/25/2007
15:52:52
| RE: Multiple Cylinder Misfires
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check each and every CAP CONNECTER inside and out for carbine tracks. Also do the same with your coil. If the connection side (top) of coil is dirty, clean it. Have your battery and charging system check also. Make sure your battey top is clean plus remove cables at both ends and clean the corrosion.
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J and J Auto
GenII
1/30/2007
02:57:39
| RE: Multiple Cylinder Misfires
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Message:
check your cap rotor
NAPA MO26 & MO28 cap and rotor solid brass incerts
around $15
stock wires around 200 ohm per foot of wire
posible fuel pump going bad
92 to 95 ngk vpower .035 gap
96 and up obd2 .040
FR4 stock heat range
FR5 1 colder most trucks reacty very well to 1
range colder try them after you replace your
o2's run about 200 miles and pull a plug it should
be taking on a light tan color if not somthing is
not right if not check fuel pump pressure
40 minimum should be 45 to 55 psi
posible
coil
crank sensor
dist pickup
all can cause multiple cyl misfire
Larry
J&J Auto
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boomer
Dodge Dakota
JOIN HERE
1/30/2007
06:59:57
| RE: Multiple Cylinder Misfires
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Message:
sorry guys, been a minute since I could check this. I havnt installed the new TPS yet. like mike said, it's probably somethin really simple, and hopefully it is just a loose sensor or somethin. the weather isnt too friendly near detroit right now so its hard to check things out since i dont have any shelter to work under. the temp. doesn't really help my truck any better either. when i was driving to work yesterday at 4:10am it was 9 degrees. awesome.
I havnt checked the cap yet, BUT I'm pretty sure that it doesnt have brass inserts so I'm gettin a new NAPA one larry mentioned ASAP. I already planned on doing the crank sensor mod so getting a new one was already in the works. when I replaced wires there was no corrosion in the old ones or on any of the contact anywhere. I thought about getting a new coil but if I dont need one then why bother right? how do you check the coil to see if its at least at minimum power needed?
Larry..anybody ever tell you that you are the MAN!?! and of course I appreciate everyones response. I like to hear any bit of anyones experience and knowledge on the questions I ask. If I check some threads I always post my thoughts, hoping to help someone out. i dont know what i would do without this site.
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boomer
Dodge Dakota
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2/27/2007
06:37:08
| RE: Multiple Cylinder Misfires
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been a while. my cousin works at pep boys and scanned my truck for me. the downstream o2 sensor is fluctuating rapidly, so that probably doesn't help at all. and it read cylinder #2 misfire, so I'm gonna pull the plug out of #2 and check it ASAP. It's not arcing or anything but I could have damaged it when I changed the plugs. I still have to get my NGK's but I heard recently theres an even better plug, the E3's? its in a post larry put up. I still havent done anything else, but at least I know it's not any other sensors. those scanners are awesome, wish I could afford one.
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boomer
Dodge Dakota
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2/27/2007
14:19:40
| RE: Multiple Cylinder Misfires
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I may be wrong exactly which o2 sensor the scanner said was fluctuating, but it did say the downstream o2 sensor was bad.
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Stephen
Dodge Dakota
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3/02/2007
15:41:09
| RE: Multiple Cylinder Misfires
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Whatever you do, change the timming chain ASAP. If it gets loose enough it will start eating away at the cover and you will have shards of metal bouncing around in there too.
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shatto
Dodge Dakota
JOIN HERE
3/03/2007
16:23:28
| RE: Multiple Cylinder Misfires
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Message:
When my 98 3.9 engine developed the check engine light on all the time miss, I did the 'throw money at it until it's fixed' thing. Replaced a perfectly good fuel injector and ignition parts. Missing remained.
Did proper diagnosis. Burned and otherwise worn-out valves and seats.
Replaced the valves and cracked cylinder heads. Problem solved.
I guess bad valves will cause bad Oxy readings too.
Timing chain? I suppose they wear out, but mine is fine after 556,000 miles. I'd like to know why people say they need to be replaced so often.
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J and J Auto
GenII
3/05/2007
23:59:44
| RE: Multiple Cylinder Misfires
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Message:
maintainance and driving habits will effect chain
life
reg oil changes and easy driving things last
longer LOL
I replaced my chain at 80,000 miles than pulled
the motor and stroked it and replaced it again
the thing here is for some reason when the V6
block was machined the cam sits .050 lower in
the block than the V8 using the same chain
its lose to start with and will begain to rattle
from 10,000 miles up than they came out with the
tensioner to solve the rattle problem and this
tensioner should be used in all the V6 mags with
either the stock silent type chain or a double
roller
with either type of chain using the tensioner
which keeps the chain tight they will last
250,000 easy without jumping
also never just replace a chain the gears also
ware and must be replaced as a set
I like to set the chains in a small pan and let
them soak in oil for a day before instal never
install a dry chain it takes time for the oil to
get there a dry start will cause ware very fast
here is another place read your plugs they should
all be the same color if white all white if black
all black
but all the same a good running motor the plugs
should all have a light tan sandy color if not
there is something wrong this tells you your
air/fuel ratio is correct
also a compression test these 2 things are the
best diagnostics you can do and anyone can do this
it does not take a genious to read plugs and
check compression
if these 2 things are good look somewhere else
for your probs
sensors and fuel presure
I cant stress this enough the plugs must all be
the same or very close and a light tan color
if not you will never get good performance or
gas mileage
Larry
J&J Auto
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boomer
Dodge Dakota
JOIN HERE
3/06/2007
11:10:50
| RE: Multiple Cylinder Misfires
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thanks larry
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boomer
Dodge Dakota
JOIN HERE
4/02/2007
12:54:03
| RE: Multiple Cylinder Misfires
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Message:
revisiting this post...I just bought the o2 sensor I needed from NGK, and new spark plugs. can't wait to get this stuff delivered. I'm gonna check my cap connectors for carbon and also my coil. my truck hasnt been running bad but the engine light comes on and goes off every couple days or so.
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shatto
Dodge Dakota
JOIN HERE
4/02/2007
22:40:42
| RE: Multiple Cylinder Misfires
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Message:
Had a Jeep that died for no apparent reason.
I used to be a decent enough mechanic to set points by eye. Could-not-figure why it stalled.
It died in the driveway of a mechanic. They couldn't close the gate to go home so they looked and looked.
Distributor cap had a microscopic crack.
Moral; change the darn thing. They are cheap.
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