My friend has a 98 Silverado RCSB. It has ~190,000 miles on it with a recently replaced 5.7L engine(stock).
He put a Superchips Programmer on it. On economy the truck ran fine, no problems at all but when he switched it over to (the highest setting idk what its called) it started missing. He put 93 octane in it and has been running it for a while with the programmer set like this. so it shouldn't be bad gas.
What are the possible things that could cause it to miss

 

did he replace the wires???

if any of them are too high of a resistanche... then when the ignition is being forced to advance it will miss...

not to mention.... how big are the plug gaps??

 

Thanks for the info, im not sure how big the plug gaps are. I just asked him if he changed wires(you mean plug wires right?) and he said nope.




and he just said his plugs were burnt up too.

 

put new good quality.... platinum plugs.

and good low resistance wires.

i think youlle be ok...

and even though they should come pre gapped just check them

 

aight, ill pass on the info. thanks!

 

no problem