spark plug problems

[lildrummer420]

I just replaced the spark plugs in my car about a month ago and ever since i have been getting 4MPG worse. Could i have put in the wrong type of plug? what is the best type of plug to use? I have a completely stock 2004 L4 Alero.

[jhubbz]

Are they gapped correctly? What type did you get? Put any anti-seize on the threads?

[a.graham52]

please dont tell use you used e3 plugs. does your engine run smooth? any chck engine lights?

[lildrummer420]

yes they are gaped properly and no i am not dumb enough to buy E3 plugs. runs smoothly and no idiot lights on.

[a.graham52]

ac delcos are the way to go. hows your basic tuneup? (air filter, fuel filter). riding with any extra weight? how about fuel grade? its getting cold out and its possible they have changed to winter blend at the pumps