I've noticed that if I run any gas lower than 93 in my car I hear a clicking sound coming from my engine when I accelerate. do you think the previous owner put a tune in my car or something.
Also my car had an msd ignition thing on it before I purchased it, the guy I bought it from took it off. I read some where that msd ing. don't realy help our cars, is this true? If not I might purchase one.

 

that sounds like detonation. more than likly it has either carbon build up and this is causing extra compression etc. whihc makes it ping or nock or detonate under heavy thorttle wiht low octane or you have a car that has been chipped or truned etc..

 

what kind of accelleration does it happen under? WOT? Normal? Hard? If its only under real hard or WOT, could be your MAF sensor has a dirt buildup on it causing the engine to ping.

Do you have a cleanable filter like K&N, Steeda, or Fram Air Hog?

 

It's under normal accel. I can't hear it under WOT, but thats probably cause of the exhaust. I don't have a k&n type filter just stock.

 

Take your maf sensor off and clean it off real good. make sure its cleaned real good and DRY. Also clean off your filter. that should fix the problem. I had the same with mine but mine was only under WOT or very close to. I also only noticied it AFTER my SCT XCAL 2 tune.