The same problem on my 2005 accent 1.3 cdx and I'm using a lot more fuel it may be one of the sensors or a injector not working I will find out want it is .

1. Excess fuel consumption can be caused by a lot of things. One of them is tire pressure. Other things that can cause issues like this are air filter being dirty, bad oxygen sensors, bad air flow sensors, VVT issues on the cam.

This is what it looks like

Venkata, According to Injectorrx.com: "
Fuel injector symptoms for bad, faulty, dirty, clogged, or leaking injectors are :

• Starting issues



• Poor idle



• Failed emissions



• Poor Performance



• Engine does not reach full RPM



• Increased fuel consumption



• Rough engine performance



• Surging and bucking under various throttle loads



• Smoke from the tail pipe



• Engine Knock or Detonation which can lead to catastrophic engine failure



• Pollution"

Venakta: I have had very good luck with a fuel injector cleaner sold by Advanced Auto called KX44 but some people like Seafoam. It is a cheaper place to start than with a mechanic.

You need to scan the ECM to see if there are any stored DTCs. Just guessing, it sounds like a bad cam or crank sensor. They can be temperamental when they get warmed up, if they are bad.

try the cam sensor too

bad oxygen will idle speed also clogged fuel filter,faulty fuel pressure regulator, dirty fuel injectors will cause engine to rough idle.

Check that the timing has not jumped, incorrect timing will trigger a cam sensor code as the ecu can not work out the correct position of the cam.

John

With the key on,the fuel pump is only activated for 1 second,the off,until the vehicle is turned over again,then it will come on again,checking power to the fuel pump,is not easy to do,,I am thinking maybe the fuel pump is coming on,but the injectors are not pulsating,replace the crankshaft sensor ,it controls spark,and injector pulse.

Check the electric stop on the injector pump is working.

you will find its due to a sensor problem