Friends got a B16, sometimes, not all the time theres this clanking ( sounds like somthing is jumbling around in the engine) we cant determine where the sounds comming from, it sounds like from the timing belt cover area, but it also sounds like its from the back of the block, we cant pin point it

As for car performance symptoms, the car is dumping fuel hardcore, like enough to make your eyes burn, i think because of a bad o2 sensor? how can i tell which one is bad? theres 2 right on the stock exhaust manifold


Also after driving, and gunning it, right after he lets of the gas the check engine light comes on, and stays on.. but after u turn it off, start driving again, and after gunning it again, and letting off the gas it comes on again

 

Since it's pulling a code did you try checking what the code is? I believe O2 codes get reset once the the car is turned off.

 

It could be piston slap aggravated by the over-fueling of the engine, or maybe low oil pressure. What kind of codes is it throwing? I dont think an O2 sensor that **** the bed would dump enough fuel to make your eyes water. Now a stuck injector(s) would. Does the car have a factory ECU or aftermarket?