eddieo45

(yes, I searched the forum first) I'm getting cylinder misfire codes. CEL will come on, car goes into limp mode, etc. If I shut it off and leave it alone for a while (once was an hour, once overnight) it pretty much resets itself ---CEL stays on, but car runs okay-- but I know if I floor it, it'll limp again. I'm ordering the ignition cables from Fastlane (F1020141213 $205 for set of 12) and want to get plugs, but there's 4 different choices. I've read that the platinums are no good, but does anyone have a recommendation?
__________________

Josh K

If you do your own maintenance, just stick with some Bosch 7557 Copper plugs. They have to be changed more frequently than platinums but offer better performance. Don't waste your money on Iridiums

Steve Clark

Have you considered that it may very well be something else?. Rather than just throwing parts at it, why don't you find out the actual cause of your misfire?.

eddieo45

Steve:
OBS II had every cylinder (except 3) misfiring, and with 70K+ on it, I figure new plugs and wires can't hurt. What could I do to more accurately find the cause of the misfire?

vinamg

At 70k, I would also change the wires and plugs. My brother's C320 started misfiring @ 75k (bad wires).

BTW, your engine is designed for platinum plugs. The problem is when people start installing them in cars that were never designed for them (M103, M104, M119, etc.).

Steve Clark

While plugs at that kind of mileage wouldn't hurt, I doubt that the plugs themselves are your source of misfire.Plug wires are a more likely candidate, although without going to the dealer you are still throwing parts at the problem, hoping to stumble across the cure.

Think about it...how would spark plugs alone suddenly cause half (I assume you have 6) of your cylinders to suddenly begin losing spark?.Modern ignitions have so much spark energy that they'll fire under atrocious conditions if it's delivered properly and on time.

I suspect the cause of your troubles is further upstream.

As vinamg posted, the best replacement plugs are whatever you car came with.

eddieo45

By that do you mean the distributer? something else? clarification: 5 of my 6 cylinders (all but #3) misfired, and the problem is worst when it's wet. I tend to avoid the dealer, but was there recently because the parts department told me there was an open campaign on my car for harmonic balancer; when I arrived for my appointment, service told me they were mistaken. To salvage the wasted trip, I asked them to read my CEL codes, for which they asked $119.00; I chose not to, and had my mechanic use the generic OBSII (for free) instead.

Kestas

What's the maintenance history of the car?... has anything been done besides fluid changes?... maybe it just needs a regular tuneup.

I agree with replacing the plugs and ign wires. Stay with original-type equipment spark plugs (platinum).

It's a long shot, but if it's misfiring under heavy acceleration, maybe you're getting fuel starvation and the fuel filter needs to be replaced.... just a thought.

eddieo45

I've had the car 2 years--since it had 50K and it now has 76K--and I've changed the MAF and fuel filter in addition to oil. I've never been thrilled with the fuel economy (18mpg or so), so I'm kinda hoping that plugs and wires might improve that. BTW, I was told that my OEM plugs were NOT platinum.
Also, what would be part of "a regular tuneup"? In the old days, that meant plugs, points, and maybe distributer cap. What's it mean today?

Kestas

Tuneup for driveability concerns include: plugs, air filter, fuel filter, clean throttle body, ign wires.... not a whole lot nowadays.... and some of these things are only done on an as-needed basis.

Find out what plugs are original equipment and stick with that. I don't know what's original equipment.... my comment on platinum is based on vinamg's comments. And don't assume the correct plugs were put in at the last spark plug change.

Driver55er

If you are interested I have Bosch 4418 platinum +4's for sale (16 available).
I believe they fit your application.
$4.00 each shipped.

Thanks,