I've had my 93 blazer for 3 years now, last weekend I gave it it's first tune up. I put on a mallory coil, mallory cap and rotor, mallory plug wires, and AC plugs. There wasn't any reason to do the tune up, it was running fine, I just wanted to upgrade the electronics and see how the plugs were burning. Well the plugs in it were autolite, that's not what bothered me, it was the gap that they were all gapped at 0.50 thou. the gap should have been 0.35 thou. I gaped the new AC plugs at 0.35thou. I didn't notice any difference in how it ran with the correct plugs and gap. So my question is why even have a gap requirement, if my blazer ran the same on a 0.50thou. gap as it does on a 0.35thou. gap?

 

ive heard stories of cars being gapped wrong and running bad. but yeah ive checked plug that were like .060 when they are supposed to be .035 just from being old and the car ran fine.

might just have to do with performance

 

gen 1 .035 gen 2 blazer .060. Also if your adding high output ignition the gap needs to be bigger for increased spark. Do your homework before upgrading

 

^^^^ yep...

although i gotta say if you have "high output" gap em the same way. factory coils put out a poo ton. most aftermarket coils are worse,if not the same. Ive ran 4-5 of em.

 

The funny thing about this is I have a 2000 Xtreme and have to run my plugs at .45 any bigger and the truck gets a bad misfire, well worse then normal. Now I am kinda thinking I need to look at the cheap auto zone coil I installed a few years back