This may seem like a strange post, maybe im even being paranoid...but however stupid it sounds lets see what you guys think. I as some of you probably already know have had my engine rebuilt...It runs good, the break in period is just about over. One day while driving at slightly under a quarter tank of gas, i noticed the car jitter a little at a light. I thought maybe bad gas, so i switched my gas, i usually put Mobil in it now. Nothing but 93 octane goes in the car. I fixed my stumbling start with a new battery, apparently mine was going dead. Also i fixed my power steering whine by flushing the pump, and adding some conditioner--silent now-- Now, sometimes when idling i hear a slight ticking....very very faint. Its not steady it goes away and comes back. This is my first SHO and since ive had problems from the get go maybe i dont even know what its supposed to sound like, lol. I seem to notice the little sounds more when the car is low on gas. I mean like quarter tank or slightly below...I dont let it get redline before i fill it, thats the lowest it ever gets but...anyway the car was a repo. Is there any possibility that the previous owner out of spite could have put something in the gas tank? Is there any way to check, or is it just to replace or not to replace? I think i may be being a little paranoid, driving myself crazy with every little thing i hear but after what i paid for the rebuild...Any thoughts on this?