I know the sparkplug issue has been addressed many times, but I did a search and didnt find an answer.
I justhadthe plugs and wires in my 1995 Z28 done, with the AC Delco 41-906 plugs, and AC Delco wires, the mechanic said that he did not gap the plugs and said that they were already pre-gaped!
I check the website (apwonline.com) thatI got them from, they claimed that they were pre-gaped.
After the change, I noticed the car was abit sluggish, soI took it back, made him take out one plug and it was 0.55 versus the factory spec at 0.50.
Should that be a problem?
Does thegreater the gap space increase power or decrease power?
He said it increases power , any advise?

I did also change the ditributor cap and rotors, water pump, pcv valve, fuel filter, all AC Delco.

 

Too small a gap will allow the plug to fire before full voltage is reached. This can result in a spark that is cooler than normal and possibly cause misfire. Too large a gap may also result in a misfire if the system is not capable of generating enough voltage to jump the gap. Also if the system has no problem making enough voltage, the large gap may have more resistance than the plug wires, in which case the spark will jump through plug wire insulation causing misfires and crossfires. This being said, increasing the gap by 0.005" shouldn't make much of a difference as it is within wear limits.
One problem you may have is that the plug you purchased are not the recommended plugs for your car. According to the AC Delco catalog The AC 41-906 is for 94 & 95 cars, the 96 car should be using eitherAC 41-943 double platinum or the AC 3 single platinum rapid fire. Of these two the best choice would be the # 3 rapid fire which is the one that best matches the original R45LTSP plugs installed by the factory. The LT1 does not need double platinum plugs because all plugs fire from center to ground. Additionally, platinum is a long lasting metal but a poor conductor, and doubling the amount of platinum makes the plug harder to fire.

 

Thanks for the info, so in other words I need to change the sparkplugs to the rapidfire plugs?
Will that make a significant difference? or is there something else that I am overlooking that made the car lazy.

I do use premium gasoline and I did use an fuel injector cleaner recently.

Thanks.