2003 Tacoma Stutter

Hi everyone,

I am hoping to get some help diagnosing an issue with my Taco.

I am currently experiencing what feels like a misfire/stutter when accelerating, usually under 3000rpm. I notice a major loss of power when driving and when I try to accelerate the motor just stumbles. It only happens once every couple of times I drive it and it usually goes away after a minute.

The truck has thrown 4 codes.

- P0136: O2 sensor This has always been bad since the new exhaust does not have a downstream sensor.
- P0401: EGR Insufficient flow, this has been there since I bought it, I can't seem to figure it out.
- P0442 Evap system small leak
- P0446 Evap system leak

There is a hairline crack in the gas tank that leaks only when filled over half a tank so I have been running under a half tank for about 4 months as it's my daily and I haven't had time to replace it.

Plugs all look fine.

The two Evap codes came up about 2 weeks after the stutter began, could they be the cause?

Also this morning I noticed the oil level was VERRY low.

Any help would be much appreciated!

2003 Tacoma 2.7l with 250 000kms