2003 Honda Civic EX. Around 20k miles. The EX has the 127hp VTEC engine unlike the LX that has the non VTEC engine. I know that does not matter much but lately the car has been extremely sluggish compared to when it was newer. The car cannot go faster than 45Mmph uphill. I know the Civic is a economy car but performance has never been this bad. Also gas mileage recently has gotten about 15% worse. I have taken it into the Honda dealership every 3000 miles to get the oil changed, I also noticed that they always put to much oil in, maybe 1/2 to 2/3 a quart to much in. Did this permanetly damage the engine making my car sluggish? I changed the airfilter out around 12k miles with a genuine oem Honda air filter. I know cars lose power but the sluggishness is very bad. Could it be something like a sparkplug not working correctly? Should I just have them hook the car up to a computer for diagnostics? I am in work and school 7 days a week at the moment so I think I will setup a appointment after next week. Any suggestions if there is a problem with the engine? Would this be something the Honda warranty would cover? Thanks
