I have a 2003 sunfire.. Today a knocking sound started when I push on the gas.. I checked a website with sounds from motors and it sounds like one I found called slappingpPistons? How much of a problem do I have on my hands

Slapping pistons don't just suddenly happen, could be rocker arm noise. have you checked the oil level?

I feel like I put oil in it all of the time.. I checked the oil less than ten mins after I noticed was a quart low so I out in 10w30..taking it in tomorrow for a check up the knock may have been there for a while maybe my muffler is kind of loud and once the car gets speed the sound isn't noticeable but when I start speeding up it is loud

Definitely get it checked out.

If it is in the bottom end (pistons, crank, rods) it's a rebuild (or you could try to nurse it along with various oil additives) . If the noise is from the upper end (valves, lifters, rockers) it's a much easier repair. You can isolate the tick/knock from a bad rod/piston bearing by pulling the plug wire for each cylinder in turn and running the engine, and see when the noise goes away.

If it is a rod knocking, you will destroy the engine block in a short time.

How does this slapping piston happen

I wad driving down highway I been kinda feeling like I was gonna be needing oil soon and as I'm driving this crazy ticking sound started and got worse with acceleration I added oil seemed to help a bit someone told me my air intake hose was missing when they checked the oil and said it was bone dry I put oil in again it seemed to run fine at first and eventually after 10 min got rough all over again

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