2000 Chevy Malibu 3100 V6 problems

I’ve got a 2000 Chevy Malibu with a 3100 that has a drive ability problem. Vehicle starts and idles fine. I step on the gas 3/4 of the way, no problem. I floor it (wide open throttle) and the engine just bogs down, a complete loss of power pretty much. The tach only reads at about 4000-4200 rpm’s at wide open throttle. When driving and flooring it to pass on the highway I get the same effect as mentioned above. Another issue is when driving occasionally the engine surges and the rpm’s fluctuate a bit, not a lot, but it’s noticeable. Any ideas on where to even start on resolving this or what could be causing these problems?