I'm creating this thread to increase exposure of what appears to be a very common issue (affecting 100% of Cruzes so far). This stemmed from the following thread:
My original experiment was to increase spark plug gap over what they are gapped from the factory and test for measurable gains in fuel economy. What I didn't realize was that I had actually gapped them to the correct spec, and they were gapped much too small from the factory.
AllData specifies a spark plug gap of .033-.037
for the 1.4L Turbo
motor. Reports so far have come back with .024, .025, .026, and .029
as measured spark plug gaps from the factory iridium plugs. These should have been pre-gapped from the distributor, but clearly weren't.
Coinneach checked his spark plug gap on his Cruze LS with the 1.8L N/A
motor and found a .020
spark plug gap, which is absurd for a N/A motor and is smaller than he or I have ever seen before in any engine. He increased that to .035 and had the following to say when I asked if he noticed a difference:
Like a whole new beast. It's not quite as zippy as the 1.4T in the Eco that I drove when I was shopping, but it's a *censored* of a lot snappier now.
I currently don't know what AllData specifies for the Cruze LS, but if someone can get that information into this thread, it would be of great benefit to everyone. Hopefully, someone will get a tutorial/video made soon. There are significant performance and fuel economy gains to be had by correcting
the spark plug gaps on these cars.