I had the same problem with Bosch Platinums (regular) a long time ago.
Turns out it was the wrong heat range.
-----Original Message-----
From: fawcett@uism.bu.edu [SMTP:fawcett@uism.bu.edu]
Sent: Saturday, January 30, 1999 1:59 PM
To: DAKOTA-TRUCK@buffnet.net
Subject: DML: Bad Knock/Bosch +4's/Plug Hype
I finally got a chance to check out my truck today... I took all of
your
suggestions and tested the hell out of my engine (Thanks Again!). I
started by ripping everything off --plug wires, distributor,
rotor... you
name it I had it off! Rotor and cap looked liked new (cause they
are after
only 10k miles ;-) so I reinstalled it and used some dielectric
(sp?) goo
on the contacts. Next the wires were put back on in meticulous
fashion...
You guys have got me talking to myself with the suggestion that I
might
have crossed wires! :-) All wire sockets were liberally coated with
the
dielectric grease before being reinstalled. Next I fired up the
engine
(smooth as silk) and tested each wire one by one... All of the
Magnecor
8.5mm wires are perfect. Finally I pulled the plugs in cylinders 3
& 5
(you may recall that 3 showed some carbon fouling, while 5 was
crystal
clean) and switched them... In classic dealer speak, I got a big
ol' NTF
report on the static test of the engine. Sooooo, on to the road
test.
Things seemed better on the "mild" highway grade so onto the big
rauncher
grade. Up I went with the cruise pegged at ~70 mph and the tach
reading
~2K rpm... Just about 1/2 to 3/4 up the hill all hell starts to
break
loose. I start getting the knock maybe even some detonation, the
engine
starts to surge then stumble, surge, stumble, surge, stumble... OH
SH*T!,
there goes the MIL (check engine light)... fast blink... real
trouble...
must eject... Major Tom to Earth!, Major Tom to Earth... mayday,
mayday,
mayday... I'm going down fast!! Must, act, quickly,... not much
time
left... everything is growing dim... I kick off the cruise, shut
down the
O/D and get over to the slow lane as fast as I can... Like the eye
of a
storm everything works fine once I slow it down and take out the
O/D. The
MIL stops and never comes back on again...
To make a long story longer, the Bosch Platinum +4's suck under
heavy load.
I would not recommend them to anyone that has to do *any* heavy
towing or
lives in a mountainous region. I've driven this highway grade 100
times
with the stock plugs (cheap Champions) under the same conditions
without
any problem whatsoever. It's too early to tell if there is any
advantage
to these plugs as I just put them in about two weeks ago so I can't
comment
about their longevity. Moreover, I can't tell if they have done
anything
for fuel economy either as I have spent so much time idling the
engine to
test it and gunning it on the street to see if/where it starts to
knock.
Anyway, that's my story! If you read this far, I'd like to say
THANKS! to
those that sent suggestions or condolences on my plug problems...
Your
comments really helped!
Tom
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