So here's my dilema...I purchased new set of AC Delco spark plugs and I ASSUMED that they were already gaped to the right specs. We'll turns out today my uncle who owns a 2000 silverado did the spark plugs on his truck today,also ac delco but he checked the gaps before putting them in, it turned out they were at .40, on the engine specs it says they need to be at .60, so that means they aren't pre measured out the box. Looking at my specs on my 99 blazer the gaps need to be at .60 as well, the thing I already put them in, so I'd like to know if it is crucial that I take them out and calibrate them at .60 or if I should just let it be and wait til the next time I replace them?????

 

You should just do it. At the least it will give you better fuel mileage. Worst case is unburned fuel dumping into and clogging the cat.

 

Yeah it only takes a few minutes to pull them out and set them properly. And buy yourself a gapper, they are like 2 bucks. Also, those same plugs may have many applications and many gap settings, so dont assume they are OK for your vehicle. Worst case is the electrodes wearing out faster and a crappy burn...

 

Out of curiosity, which AC/Delco plugs are we talking about?

 

Thanks for the advice guys, it just sucks that I have to detach the steering column to get to that middle plug, sort of a pain. But its gotta get done. As far as the plugs I cant remember the number I'll get it when I take them out on tuesday. I got them from Napa auto parts and they're the ac delco platinums I believe. I've also heard people say that if the cat converter is clogged that will reduce your your MPG, is that true? I'm averaging about 60 highway miles per 1/4 tank roughly 240 miles a tank. I'm trying to do everything possible to get the MPG higher. A cat converter may be the next fix up. anyway, i'll keep u guys posted, thanks again.