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Spark plug gap size?

17K views 16 replies 11 participants last post by  SainT 
#1 ·
What are the gaps for an Astro? Should they be 0.060" or 0.040" Pulling all the spark plugs were easier than i thought lol
 
#15 ·
As a general rule you want the biggest gap the ignition can reliably fire but if you "out gap" the ignition that is worse than a too small gap. When I put the '99 LS1 in my '98 Astro the engine had NGKs in it. I replaced them with ACs cause I thought that would be OEM and then found out GM put NGKs in the LS1s.
 
#16 ·
i have to reply this thready by duty. there is talk here of not having to gap plugs. that is total hog wash. and here is why. while i did not work on this vehicle i work closely with the tech that did. it was GM SUV and it have been in to two shop three times and had everything in the ignition replaced. no one could figure out what it ran like shit. one quick check of the "pregapped" plugs showed that they were way off, and i seems odds are that the came that way out of the box. it's like factory try to meet quotas and ram stuff out the door as fast as possible or anything like that. so for anyone googling "2001 astro plug gap" on google know that it may be a good idea to GENTLY check the gaps on your plugs, and yes the iridium looks quit dainty i could see how they could easily be messed up checking the gap.
 
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