I have had this problem with these engines and with alot of the cheaper aftermarket ignition parts,
The fix i found was matching it with the better automotive cross overs:
- if it has the spider style igntion cap its a 1999 GMC Safari
- if it has the tall cap its a 1995 GMC Safari and buy decent cap and rotor
as for plugs get the 1995 GMC Safari AC Delco Non-Platinum plug (i find they with stand the heat of especially propane trucks)
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