Have a 98 v6 firebird and when I start it it fires right up but when rev
hear. Tap with acceleration no lose of power
That would be your lifters & rocker-arms. May need to check them out for adjustment.
Has the vehicle been serviced regularly? I would drain the oil and change the filter then add a quart of Marvel Mystery Oil and fill to specs, then drive it as you normally would and see if it tapping starts to go away after the first 100 miles, if it does then there was some varnish in the lifters and the MMO cleaned it out, if it doesn't then you will have to dig into the engine to find out why they are making noise, could be an adjustment but then again worst case it could be the camshaft wearing out.
Bad gas? Try a quick fix put super unleaded in it that's what was wrong with mine.
I agree with Rowefast. It's probably your lifters. We've fixed this problem by using 5w oil in the colder months and 10w in the warmer months. No tapping heard for 5 years straight now.
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