my car is getting horrible mpg and when at idle it will bog so low it just about dies and occasionaly does. Also when im driving it will sputter and miss, but when i actually give it some gas it doesnt do it. ive got no cel light, changed plugs and plug wires. could it be a vacuum leak or an 02 sensor or what just help me out. one more thing i just changed the plugs a week ago and now already black as can be. any ideas? would appreciate the help

 

change your cap and rotor as well, you didn't do a full tuneup.

i would also recommend changing that fuel filter too if you haven't already.

 

alrite ill try that and then get back to you, just didnt think that would cause it to bog at idle