My Ford Focus 1999 has recently been making very strange boy racer noise, it's sound like it comes from the passenger side and every time I use my acceleration 20-30mph is the worst. It's horrible noise and goes away when constant speed like 40-70 mph but other times when I slow down and use the accelerator its makes that awful racer sound. Any one knows what it could be I really have no money so don't want to take it to a garage incase they make me pay a fortune. I've noticed my petrol goes a lot quicker also and have to top in up a lot. Just need to find out whatever the problem is and try to do it myself! Thanks