Sputtered when idling and almost felt like it was going to die. Almost 24 hours later engine light is on. Diagnostic tester showed cylinder 2 misfire. Where do I start. After reading other forums, plugs, etc changed out didn't rid the code. Is it possible for a dirty sensor somewhere?
Huh what is etc? is it hard to type facts for free expert help>???
09 JK , I own a 08, stick. 3.8L V6. right?
you never said mileage, why?, mines at 60k,
P0302, is that hard to say , that it one only just 1 code,and
you reset it, and it COMES BACK, you never said so...
(to reset it push reset on the scan tool)
or learn which fuse to pull, I have real FSM in hand. can answer that. (its marked OID) in the TIPM fuse box, pull m3 fuse
for say 5minutes, all codes are forgotten now. 3.8L JK
that (my had to guess) code means, this.
weak combustion on #2 only. (slow piston acceleration is a fact)
so if all 5 others burn right how can just #2 fail only.
ANSWERS:
well its NOT FUEL MIX is it.
leaving only these.
1: sparkplugs gapped wrong, did you set them or guess?
to SPEC<, is the answer.
2: spark plug wire #2 to coil pack lug 2, is this new?
we work cheap to expensive ok./?
3: weak compression on #2. check that WOT?
wide open throttle (about) but never at idle position.
4: injector issues. #2 only (swap injector or learn how to do balance tests and leak down test on them, out of BOOKs
not internet bs rumors.
there it is...
the order above is by complexity and cost.
throw in bad coil but no miles stated so ,i guess low?
do not mix coil wires, or it will misfire. it has only 1 way to do it.
the code not presented P0302
means this in pure physics (best)!
it means the piston velocity on #2 was slow.
the PCM measures the rate of change, at firing. (of each piston by federal laws,OBD2)
and if slow, that means its weak and means.
weak combustion ! #2
it does not mean only spark , see?
weak has 3 major failure paths
bad compression
bad spark
bad fueling. (in that order)
how ever statically, skipping tuneups is #1 cause.... of misfire for 100 years now.
Given.
only one code is stored,and resetting it comes back driven....
where do you start, well that is a long story and book, (there are vast books on topic)
ill not do one here.
what did the spark plug look like , before changed out.
black, oil soaked, green with antifreeze
white, or tan,? dripping in fuel, or looks normal. this is like the fist thing.
if the HV wires from coil pack to the plugs
at about 100k miles.
id even inspect every inch of #2 wire.
and make sure its got 3k ohms resistance per foot, not infinity. I run NGK mag wires.
they read 0ohms but are reactance wires.
then if all that fails, I check compression on #2, 120-150psi is spec, sea-level reads max. less in Denver CO.
ok spark good, compression good.
i then scan it , using live data
i then look at all PID data for wrong readings. RTM
this is covered in all ASE classes
and not something I can cover in one page.
I look at pendings too.
and at the freeze frame for P0302, to see of other key parameters read wrong for that.
ECT reads 180F or more.
O2 sensor works at IDLE and swings,
and swing centered on 0.45vdc. fast.
if not, I work that issue.
this post is for you and other JK owners
so if its too long, others will find it useful.
(read the chapters on how misfire monitors work for best results)
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Bad miss at idle?
http://technoanswers.blogspot.com/2012/01/bad-miss-at-idle.html
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While stop engine idles
like cylinder missing?
http://schematicsdiagram.blogspot.com/2012/01/while-stop-engine-idles-like-cylinder.html
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Engine Misfire codes for
car?
http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html
Engine Misfire codes?
http://schematicsdiagram.blogspot.com/2011/12/engine-misfire-codes-on-chevrolet.html
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Misfire on cylinder 4?
http://schematicsdiagram.blogspot.com/2011/12/misfire-on-cylinder-4.html
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Oil on spark plugs and car misfires?
http://technoanswers.blogspot.in/2012/02/oil-on-spark-plugs-and-car-misfires.html
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This will help.
Thanks.
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