1997 Ford F-150 acceleration

With it making that sound check the serpintine belt and pulleys. The belt tensioner will make all kinds of noise when going bad. One way to check is get a old water hose and cut it into a piece about 2 ft long. Have someone rev up the truck and with one end towards his ear and the other on a non moving part check around the belt and pulleys. Remember don't put it on a moving part. There are a thging that looks like a doctor shethscope that costs about $4.00 when you can hear the noise keep checking to pinpoint where the noise is coming from. You might hear it but keep checking to get closer to where the noise is coming from. Have a scope and it will pick up noises that the engine is making.