Engine noise

I have toyota camry 99 LE 5SFE federal emission engine. The question is about the noise the engine makes when driving. I would call it pinging but it comes from underneath of the engine it happens when driving. Also engine hesitates on low rpms and oil gets smell relatively quickly. All possible tunning was performed. The car has had 5 owners before and the last one had no idea that you need to change oil. Anyway from what I’ve read it sounds like one of main bearing went bad. I would appreciate advice. Thanks.

I think main bearings make more noise when car is first started. They also make more of a knock at least the ones I have heard.
Does oil have a gas smell? There are a few different sensors that can make it run rich, to much gas.

Thank you for the reply. It does make knock when you open the throttle very quickly. I’ve checked all sensors most of them were replaced as well as OEM sparks and spark plug wires. About smell, you know it’s hard to tell if it smells like gas but definitely gets some smell for less than 500-800 miles. We have another camry almost identical one it does not do that and it has twice more miles))(170K)! I’ve checked timing, fuel pressure, vacuum pressure around the throttle, the cylinder head was restored, all seals and gaskets were replaced… Any ideas?)

And one more thing the car is making a poping sound when you the throttle quickly. Thanks.

You left out something important…How many miles on it??

It has 91K, timing belt, tensioner, spring, water pump, all seals and oil pump were replaced.