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bosh platinum spark plugs

01-16-2005, 07:18 AM
Hi, new to this board i have a 1994 jeep grand cherokee with 4.0 it has 147k miles on it. I put the bosh platinum spark plugs in it yesterday! question: has any used them in this application and are they better than the standard autolite spark plugs, any pros or cons on this. Thanks for any replys

01-16-2005, 08:40 AM
First of all take those plugs out and throw them as far as possible.
In a Jeep they are junk!!!!!! Can cause mill light to come on and ping,the Bosch are way too hot.
The Champion plugs that came in them work the best. I am not a Champion plug fan but Chrysler and Champion spent years developing the correct heat range for their engines.

01-16-2005, 08:48 AM
Thanks for reply i was going to get champ plugs too, well can leave them in for at least a week or so till i can get new ones, hate it when i buy something to it is no-good!

01-16-2005, 10:13 AM
Yup I agree with JJ, I have the Bosch Plat+4 (there are suppose to be good better - gas milage and combust fuel more efficiently) but they do none of that they are junk, after putting them in about 2 months of driving my milage on the Overhead consul reads 9.7 MPG, b4 putting in the bosch Platinum+4 my milage was 14.6 MPG, I am gonna be replacing mine next week.
But I am prolly gonna go with the Autolite AP3923, they have shown best to get better Mileage and a tick of more HP. but if they don't help then I will go back to the Champions.

01-16-2005, 10:54 AM
Hmm I have the Bosch platinum in my 97 GC and they seem to work just fine. I just came back from a trip and I got 17.8 MPG according to the overhead computer.

01-16-2005, 10:58 AM
champion might be cheap plugs but for a jeep,they seem to work best.i completely agree with justjeeps,i have seen quite a few driveability problems caused by people wasting their money on bosch plugs.

01-16-2005, 07:32 PM
I have bosch plat+4 in my 99 gc 4.0 for about 2 years and about 30k miles never had a problem with them.

01-16-2005, 11:32 PM
I have used platinum , self cleaning , and they seem to work , but the so called splitfire plug have made me overhaul the enging more than once , driving in hot weather , overheating , causing bits of the piston to fly off and slam the electrode flat
do your self a favor and use the cheap recomended plugs , theres no such thing as a free lunch

01-17-2005, 05:48 AM
Thanks for the replys, pulled the bosh plugs out and i put champion plugs in!

01-17-2005, 04:07 PM

What free lunch??
Bosch Plat plugs cost 4x's what regular champion plugs cost.

I'm confused what do you mean you had to overhaul your engine more than once because of splitfire plugs? (never like splitfire myself)

If they damaged your engine once why would you reinstall them?

01-18-2005, 12:09 AM
ok mikie , will give you the honor of a reply , i tried the bosch plat , split fire , and all the other gimmicks they came up with, lessons learned from trying to get better than 8 miles a gallon in an old dinosaur , as to no such thing as a free lunch , that s the bottom line of 7 years in college , if you learn nothing more from that , you saved a bundle in tuition , best to you

01-18-2005, 09:48 AM
Many years ago when the "splitfires" first came out I decided to do some testing using my 64 GTO. It was my daily driver at the time and I kept very accurate records of fuel consumption, tuning and drag strip times. The splitfires lost 2 tenths in the quarter and 2 mpg. The best plug for that engine was the Accel U-groove.

I just bought a set of Bosch Plat+2 to "try out" in my Jeep. Can't remember what plugs I am currently running but I know they have over 100k on them and still making 20+ mpg. I'm thinking AC's.

01-18-2005, 11:21 AM
i have a 99 gc with approx 100k with bosch plat 4 and i like them i got about 2 mpg and they have been in for about 12k with no problems. initally when i put them in it seemed to start better and the old plugs had lots of life left in them

01-18-2005, 12:02 PM
I have been using the champion plugs since I got my Jeep in 99. Gone through 2 sets since then. They didn't need to really be replaced, but did anyway.

01-18-2005, 04:43 PM
Ok Glassie

So let me understand this,

You overhauled your engine a couple of times and reinstalled plugs you say caused the damage.

You were in College for 7 years

and you brake my chops.

BTW you don't need to honor me with a reply.

Better to keep quiet and be thought a fool than to speak and remove all doubt.

01-21-2005, 11:13 AM
Last night I pulled my plugs since I am doing other tune up and repairs and it turns out my 100k+ plugs were BOSCH SUPER R6 765 with single tip electrode. Measured the gap and they had worn to .065 thousands! Cap and rotor looked terrible (covered in brown dust) and the distributor shaft wobbles!! All this and I was still averaging over 20 mpg! I bought a low mileage used distributor off ebay last week for a spare cam position sensor but looks like I'll be swapping the whole thing in!

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