[Gene_CA]

My 2000 has about 75,000 on it. I replaced the plugs a few years ago. Mileage slowly went down to just under 12.00 in short run city driving. I put in a new set of NGK G+ and the last tank showed 14.2. Outstanding. Is that reasonable? I grew up changing plugs every 10k in my Ford flatheads and later the 289s. Unleaded made the big difference. I just do not believe 100,000 makes sense.

 

[William Wiles]

You just had a good month. Watch it over 8 or 10 tanks and see the real mpg. One tank can change it that much just by having a different angle of the van at fill up or on trip on the van on the freeway. Unless your plugs were really crappy changing them should make no difference at all. As for your old flat head ignition systems were a lot different then. In the advent of electronic ignition, lead free cleaner fuel. Tighter engines, etc plugs today should last 100 k with no problem. Gaps widen some but the system is designed to jump a very wide gap. I designed an electronic system for my 75 Nova back in 76 and the plugs in it seemed to last forever.

 

[sugarqfx]

i beg to disagree, on my old civic, accord whenever i change my spark plugs i do get better mileage i get an additional 1 up to 3 miles per gallon! but not as drastic as what you said! now i own a 1999 odyssey will do that to!

from what i do understand better spark, better burn, better fuel economy

 

[OdyinNH]

The old Civic/Accord only had regular NGK plugs that were recommended for replacement after 20k or so. The Ody has Platinum plugs which go 100k+. Mine were like new when I replaced them at 104k and I didn't notice any difference from new to old. Same good MPG's. The recommended plugs cost a bunch more but nice to ignore them for 100k

 

[sugarqfx]

i was using bosch platinum on my civic and accord but everytime i replaced when they needed replacing i saw 1 to 3 liter difference in mileage, i might try some bosch platinum 4 on my odyssey! only thing is they cost 15$ each at napa

 

[New Dad New Van]

I wouldn't use the Bosch on the Odyssey. OEM NGK Platinums $$$ recommended at 168,000 kms.

 

[sontakke]

i was using bosch platinum on my civic and accord but everytime i replaced when they needed replacing i saw 1 to 3 liter difference in mileage, i might try some bosch platinum 4 on my odyssey! only thing is they cost 15$ each at napa

This tells you that Bosch Platinum do NOT last.

- Vikas

 

[OdyinNH]

I put the Bosch platinum's in one of my cars, it ran crappy until I put the old basic plugs back in. Not worth the $$ in my book but try them out and post back.

 

[redmondjp]

All of the mechanics that I know unanimously hate Bosch platinums, especially in Hondas. It's common to see a poorly-running Accord come into the shop, which the owner has "tuned-up" at home using them.

A set of stock NGKs and it's back out the door running just fine.

And if you think that modern Hondas are sensitive to spark plugs, anybody remember the CVCC motors of the 70s 80s and how finiky they were regarding plugs?

 

[sontakke]

Bosch was the first one to come out with platinum spark plugs. I used to buy them from K-Mart for $0.99 for the 83 Prelude. I thought I was getting great deal. After going through at least three sets in quick succession I finally learned my lesson and started sticking with the OEM NGK's.

Bottomline:- On Japanese vehicles, stick with the factory NGKs and avoid all the hard to diagnosis problem.

There are ample examples in this forum about people using Bosch plugs and later regretting it.