Just put on my xpipe and flows on my 98 gt....only thing i didnt put back was the the tails so it dumps out after the mufflers......the car now sometimes sounds like it misses sometimes....but i replaced the fule filter, pcv valve, coil packs just 2 days ago and the plugs and wires a month ago.....car doesnt do it when untill its completely warmed up then when i go to give it more gas it hits a point and acts like its missing......my friend thinks i dont have enough back pressure and if i put tails on it will be fine.....need advice