O.K. I misdiagnosed this... What I thought was a misfire is actually heavy
spark knock. It was very intermittent on a mild highway incline so I found
a steeper incline and I'm still nervous after what happened. I had the
cruise pegged at around 65 or 70 and about half way up the hill it started
to knock really badly... Before I could pull over the check engine light
(MIL) started to flash rapidly (limp-in mode?!) and the engine was running
incredibly rough --almost like it was going to stall at around 50 MPH! I
got over into the right lane, switched the O/D off and was able get up the
hill and off the highway... The check engine light stopped flashing as
soon as I got off and has not come back on since. Man, I thought I had
really screwed up my Kota!
I got back home and yanked every plug and checked the gaps as best I could
with these Bosch +4's... They have four ground electrodes so it's kind of
hard to check but they all looked consistent... The only thing I found was
a slightly higher carbon buildup on the plug in #3 cylinder and the #5
cylinder plug looked like it had never been fired (no carbon whatever).
All the others looked fine.
I checked all vacuum lines and wires and everything seems OK... I'm also
running the Magnecore 8.5mm wires which seem fine. This is the first V8
I've ever owned... With the V6's, straight 6's and 4 bangers I've worked
on it's been obvious as soon as you start the engine if one of the plug
wires is shot (or you connected them wrong)... Does a V8 still run smooth
with only 7 cylinders firing??
Is there an easy way to check if a plug wire is good or not? Any ideas on
what the heck is going on??? At a minimum I'm gonna' run out tomorrow and
get some dielectric grease 'cause I did not use it. Any other suggestions?
Thanks!
Tom
______________________________ Reply Separator _________________________________
Subject: Re: DML: Misfires -- Need Help
Author: <dakota-truck@buffnet.net> at smtpout
Date: 1/23/99 3:52 PM
You may have damaged the spark plug wires when you pulled them off. Did you
have to wrestle to get them off? I've had this problem on 2 different Daks. On
1 of them I had to pull the wire off the plug by bits and pieces. USE
DIELECTRIC GREASE ON ALL CONNECTIONS AND ON THE INSIDE OF THE BOOT.
Dr. Pat
----------
>From: fawcett@uism.bu.edu
>To: DAKOTA-TRUCK@buffnet.net
>Subject: DML: Misfires -- Need Help
>Date: Sat, Jan 23, 1999, 2:06 PM
>
>I installed the Bosch Platinum +4's this past Monday and I noticed what I
>think were several misfires at high speed -- about 65-75 MPH. It happened
>going up a very slight grade with about 1/2 to 3/4 throttle (auto tranny
>did not downshift or come out of O/D) and does not seem to happen at WOT...
>
>My truck is a '98 318 with ~10k miles on it so I don't think it's the coil,
>distributor, fuel injectors or other stuff that can cause this. I did put
>my FABM 10" back on at the same time I put in the new plugs and I did reset
>the computer...
>
>Is it possible/probable that the computer just needs more time to adjust
>and I should just wait this out or should I just go ahead and start yanking
>the plugs and check gaps (even though they were "factory preset")??? Is
>there a better way to diagnose the cause of a misfire?
>
>Thanks in advance for any help.
>
>T.
>
>P.S. I wrote to Dave (Fish) who also recently installed these plugs and he
>does not have the same symptom/problem... Thanks for checking for me Dave!
>
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