HI do you think the probleme are the fuel pump , the fuel regulator, .Man i lost around 10 mph on a 1/4 miles, I change the knock sensor, the mass air flow, my plugs look goods too, i think i gonna change my fuel pump and i see after the result! i have a k&n complete kit (air filter,and the cai) the car run normal but less power, the check engine light are not open but the code flash around 2 time per summer , I need help

 

try running sea foam to clean lines and injectors, change fuel filter. Check fuel pressure, then take a look at the pump

 

Yeah but maybe something else for 10 mph on 1/4 miles are around 90 hp lost...

 

Could very well be a fuel filter problem. Get the codes scanned and see what's in the history.

10 mph is a TON unless you're comparing it to winter times at 0 DA compared to 2000+ DA in the summer. The summer heat/humidity can cost you upwards of 5 mph.

 

sorry not a comparaison of winter/summer because the winter here i got around 10 feet of snow