When the car comes to a stop light and i sit there (manual) the rpm sometimes dips below 500rpm and makes the car shake for a second. First I tried the mikachu grounding system. That god rid of the low idle fluxation on cold start, however it did not solve the problem when the car was warm.
Next up I tried iriduim denso plugs, that didn't solve the problem either. At my wits end I decided to try indexing my iriduim plugs. This worked! No more annoying low rpm feels like the cars gonna die stuttering! Sparkplug indexing is where you take the conducting strap and mark it with a marker on the porcelean part. Then you align the conducting strap facing the exhaust port, which results in fresh air/fuel hitting the sparkplug right away!
-Enjoy!

 

Good post idea! I've got those same plugs and like them.
Am surprised that you'd have this problem with two sets of very different plugs.

Where are the other people complaining though? I mean, it's a puzzle! You had a real problem and it was fixed by your method. But all our engines are about alike, and we don't stutter and don't have indexed plugs.

I draw no inferences but am really puzzled! Yes, indexing is a good thing just as a matter of course. Never heard of it fixing a miss at idle speed, but it makes sense in your example for sure.

thanks!

 

I have noticed the problem after the car was broken in.....i was thinking i had a set of fouled plugs or something.....It's shuttering at idle with common drops to 500 rpm's and a bit of shaking....I'll try the indexing thing and let you know ...Thanks for the info

 

oh yeah btw, i have a grounding system someplace i have posted all that....if you care to check it out.......It didn't help my shuttering problem either.

 

Any way you could post pics? I am having a hard time visualizing this.

Thanks

 

This is a new one to me! Can you post up some DIY style pics and help some of us out!? Can you index stock plugs?

 

Turn off the A/C.

 

g-g-g-g-glad you figured it out

 

I have that same issue- a bit annoying at times. Pics would be GREAT and yeah can you do it to stock plugs?

 

^^
what he said

 

Index the plugs? I'm sorry, but when I put a plug in, I torque it to the proper torque and leave it...I'm not going to loosen it or try to tighten it more just to get the plug to point to the exhaust port. This will either allow you to not have the plug tight enough or maybe strip it trying to turn it further. I say no way! Like the other guy said...turn off the A/C. It's just the compressor kicking on and off.

 

How about turning off scion life !!! Smart @$$ ............

 

I don't think he meant it as being a smartbutt... There is some logic to what he is saying.

 

Oh i get it..........Roast my @$$ off down here when i paid for a car with a/c that should work properly and not screw up my idle ........but hey it's only a $14 k Scion xB not a caddy ....Sorry bout that

 

Hey, don't get ____ed at me...I'm just stating my opinion. I'm not "roasting" you or anybody...I just don't think I want to possibly strip out a spark plug thread on my ALUMINUM head trying to get the plug to face a certain way. You can do whatever you want. I'm just saying I wouldn't do it. Have fun, and invest in some heli-coils while you're at it. I hope it works for you.

 

When indexing...if it's only an 1/8th of a turn from being lined up, you shouldn't have a problem tightening it up a little more...but 3/4 turn away? I wouldn't try it...and loosening it to match up could cause serious issues too.

 

indexing is something people have done for years.....cars typically run better once done

 

I don't see any logic behind how turning the plug so that the arch faces the exhaust valve would make any bit of difference.......


Not saying that it dosen't work (in some mysterious way), or dis-creaditing what you've posted

 

^^^ Because then the spark is exposed directly to the incoming fuel/air. Having the "arch" towards the incoming mixture puts the spark indirectly out of the way.

 

Spark Plug Seat Style: Flat
Spark Plug Thread Size: 14mm
Washers Included: Yes
Washer Material: Copper
Washer Sizes (in): 0.043/0.054/0.064
Quantity: Sold as a kit. Spark Plug Indexing Washers, Copper, Flat Seat, for 14mm Plugs, Sizes .043, .050, .064 in., Set of 30

this is how you do it