I am running NGK Tr6's with my coils right now, but my gas mileage dropped from 21 to 18 in the city. I wanted to know what everybody else was running? I just have the basic mod's intake, header, exhaust, pulley, t/b.
Try switching back to stock heat range plugs. When i was selling the coil setups i wanted to play it safe so i told everyone to go with tr6 plugs. I have since changed mine to tr55s and it seems to run smoother with better mileage. Give it a shot... also HPT helps too
wow... ive always gotten very good mileage (best ive ever gotten was 34) with my tr6's N/A... but then again im running the stock ignition. i really dont see how the coils and plug combo would hurt gas milage tho.. if anything i'd like to think it would help.
Would that be stock A/C plats or ngk tr55 coppers? I wish I had acess to HPT
Brian Lorello wrote:I am running NGK Tr6's with my coils right now, but my gas mileage dropped from 21 to 18 in the city. I wanted to know what everybody else was running? I just have the basic mod's intake, header, exhaust, pulley, t/b.
your car is stock, really... run the stock temp plugs. msd coils arent gonna make any change outside restore any efficiency you have lost due to wear and tear over time....
I'm running Ac Delco plugs in my car and they work fine..... cars seem to like plugs that they where designed to have from the factory....
Thier platinum plugs though (all you can get here anymore).... autozone told me that my car came with platinum plugs stock from the factory..... I don't believe them though.
You should believe them, because for the 1st time AutoZone is correct in their recommendation to you. Our cars did indeed come from GM with platinum plat plug baby!
But I too agree, you have minimal mods, that of which have no affect other than that of the intake, on your internal combustion flow...
I have close to the same mods, and I have no problem with my stock ign, along with stock plugs...though, I think I am a little on the rich side, so maybe I should go to a colder plug...what do you think?
Anyhow, just my 2cents
-_98 Cavy Z24_-
plats were stock in 3rd gens.
iridiums work well also if you can foot the bill.
Hmmm, I've been running Champion Platinums in mine for years.
I've got the MSD DISII with MSD external coils and no problems yet.
Oh and for those that say the stock ignition is fine, try the external DIS swap.
You'd be surprised at how much smoother your car will run.
Also, I've got my plugs gapped to the full .060 where I had to have them gapped at .040 with the stock setup.
I've also tried every sparkplug out there and the Champions work just as good as the high dollar units. Besides, I change plugs everytime I change my oil so what's the use in wasting money on high dollar plugs.
8 dollars for a set of plugs isn't a bad investment for every 5K miles.
Misnblu.com
Newbie member since 1999
Thank you Dave and JBO! 
I've already got my spare IDI cover all painted up with the coils removed (left the ICM on).. for the MSD swap.... I just don't have the $$$ to finish it right now.
I was running Denso Iridium plugs for a long time and they worked pretty well...... that is until my coils started going out again and fried them.... which is why I have the conversion planned.
I'm sticking with my AC Delco Platinums though.....
Autolites are really the only plug I've ever had "Problems" with so far.... and I'll let my car sit before I put splitfires in it.... stay away from them.
