1998 Z71 Spark Plug Gap

[BowTieZ71]

Anyone know what the plugs need to be gapped at for a 1998 Z71? I have no owners manual and the truck is lagging and running bad, I got the order of the wires correct. They are AC Delco plugs. Code coming up is "misfiring on random cylinders" Thanks guys.

[GMstrong]

you shouldnt have to gap them they come pre gapped.It should be .60

[cliobogger]

you shouldnt have to gap them they come pre gapped.It should be .60

^^

 

what he said.

[rodram]

Anyone know what the plugs need to be gapped at for a 1998 Z71? I have no owners manual and the truck is lagging and running bad, I got the order of the wires correct. They are AC Delco plugs. Code coming up is "misfiring on random cylinders" Thanks guys.

 

"Misfiring on random cylinders" is a classic sign of injector issues on these Vortec engines......

I would start by getting a good injector clean/flush, if the injectors are gummed up real bad, they can be removed and soaked ... and even replaced individually if they won't clean up...

 

once the injectors are all cleaned up, then check the fuel pressure (spec is 61 to 66 psi)

 

The poppet valve at the tip of each of the injectors can stick open, stick closed, or only open partial and just not spray properly ...