i have a 2001 1500 get piping i put 91 gas in it still get some piping what can i change to fix.

I assume that you mean that the Engine is "Pinging" or in other words, you have a pre-detonation concern. If it's only doing it on WOT just before it shifts gears - don't worry about it but that's the ONLY time it's ok. Cheap or contaminated fuel, Engine overtemp, incorrect engine timing, carbon build-up on either valves or pistons. Is there a "Check Engine" light on? You could hook up an Advanced Scan tool and watch the Knock sensor input when the "Ping" occurs. A simple test without a scan tool is to hook up a timing light and watch the ignition timing while "rapping" on the heads or Intake with a small hammer. After a couple of quick whacks, you should be able to watch the ignition timing back off and then return to normal. Come to think of it - Ethanol is a big deal in some States and Alcohol is Hydroscopic - it draws and collects water from the air. Some water in the fuel system doesn't bother anything but enough of it will starve the Engine a little.