I have a 2002 wrx and the only mod is a cold air intake. When I get to 3000 rpm it seems like the turbo is coming on and off and I can feel it jerking when driving.i can here it sucking in air for about a second then it stops and it repeats this until I let of the gas. If I keep it below 3000 it runs fine. It also has the gas smell and I've read alot about it on here and havnt found anyone with the same problem. Would the gas leak cause this?