engine runs like crap

[aznbmxxxer]

the engine sucked up some water, it didn't hydrolock, just a lot of white smoke out of the exhasut. then it died and wouldn't start. i replaced the ignition coil and it started again. now when i drive, the car backfires a lot when i get on it, and the af meter is all messed up, sometimes it works and then itll go all the way to lean and just sit there and sometimes the light will turn off. so i was thinking the o2 sensor was messed up from the water. but i ran the codes and it said it was the fuel pressure or vaccum leak. there are no vaccum leaks and the fuel pressure is in specs. i unplugged the o2 sensor to make run on default settings and it runs a lot better. how do i test the o2 sensor to see if it works?

[Tofuboy]

eventhough the engine didn't sieze, most likely you have bent one or more piston rod. Did you remove/dry out the cylinders and change the oil before you start up the engine after the incident?

[aznbmxxxer]

if i bent a rod could i drive on the engine? the engine starts up and runs now, the ecu just throws codes that i cant figure out what it is. it says that there is a vacuum leak and the fuel pressure is off. but i checked the fuel pressure and its fine and i checked for any vacuum leaks and couldn't find any. and my a/f meter will sit on lean and sometimes turn off so i was thinking it was the o2 sensor. the ecu didn't have any codes with the o2 sensor. could it still be messed up even though theres no codes?

[Tofuboy]

How is the engine idling?

I am not too sure what's the root cause of the vaccum leak and the fuel pressure codes (did you get these codes yourself from the flashing check engine light?), but your AF staying on the lean side could be due to the damaged cylinder pushing out the unburn mixture out the exhaust and covering the 02 sensor. When the 02 senor is covered with carbon, the ECM gets fool by the incorrect signal and keeps leaning out the engine. You can check by looking at the 02 sensor to see if it turned black from all the carbon.

If your engine is running lean, I suggest you not to drive it until you get it fix. You can damage your engine further more by running it too lean.

[Chromedubs165db]

I'm not sure what kind of car you have, but if it is one that uses a mass air flow sensor and water got on it you may want to check that out.

[GEESERTEG]

Personally... I would go get a dielectric based Electronic cleaner spray from Radio Shack and start to go through all the connectors to the related ECU code. Also take the dizzy cap off and make sure you dont have any moisture in the cap or around control module and coil pack.. If your car is set up that way. It may be distributorless. Anyways.. after all that is done if the problem still I would go have a compression/leakdown test done.