Spark Plugs

[cjung]

Hello everyone. I am the original owner of a 2000 Tahoe 5.3 with 80,000 miles. I replaced the plugs and wires about 500 miles ago. The wires are the correct AC Delco 9748HH and the plugs are AC Delco 41-962. My question is that the original plugs were gapped at .060 and these replacement 41-962 plugs are gapped at .040. I checked the gap for the new plugs and all were correct. After installing the wires and plugs, I immediately noticed a mpg drop down to right around 13mpg. I always got better than that before. I suspect that the plugs are what is causing the drop in mpg due to the smaller gap used with them. Any idea where I can find the original plugs that had the .060 gap? Although the Tahoe is running great, I honestly think these plugs are crap when you instantly lose mpg. Thanks for your help.

 

[cjung]

An update to my spark plug problem. I looked in the shop manual and the original correct plugs were 41-932. I found 8 of the original 41-932 on Ebay and have ordered them. I will put these in as soon as I get them and get these crappy 41-962 plugs out of the engine. While doing research, I read of others complaining about a loss of gas mileage when using the replacement 41-962 plugs. A word of advice....don't use the 41-962 plugs.

I'd like to add that the original 41-932 plugs that have been discontinued are not cheap and are not easy to find. JFYI