can a bad fuel pump cause the check engine light to flash? the reason i ask is because I have a 2005 civic with 125xxx miles and experiencing hesitation when driving on the freeway (will hesitate about 4 times in a 30min drive home). the CEL was flashing on one occasion during city driving. it starts okay, low idle for about 3 seconds, then idles fine.. drives perfect the rest of the time... so i dont think its valves or bad sparkplugs. i pulled the CEL and recieved a p0300, p0301, p0302, and a p03103. was wondering if anybody has experienced an issue similar to mine and knows the fix.... any responses would be greatly appreciated. Thank you

 

A flashing MIL is usually caused by a misfire. (which are the codes you posted)

Inspect the spark plugs, injectors, and fuel pressure. You might also want to check the EGR valve to make sure it's functioning properly.

How long has it been doing this?




Since you're at 125k miles:

Have the plugs ever been changed? They need to be if they haven't been.

You do need to inspect the valve clearances if it's never been done.

Edit: Here, flip through this. It's the maintenance schedule from the FAQ's..

 

i changed the plugs at 80xxx and inspected them recently and all seem fine, I was trying to sceck the resistance on the coils but not sure which prongs.... if the valves were not adjusted properly, would this be a continuous hesitation or rough idle? how do i check the egr valve?

it has been doing this for about 2 weeks

 

Okay, you can probably rule out the spark plugs.

What about fuel pressure?


To check the coils, you measure the voltage between terminal #3 (black/white wire) and a ground. There should be voltage.

To check the continuity, connect to terminal #2 (black wire) and a ground. There should be continuity.




As for the valve clearances and their relation to misfires, a listed symptom of misfire as "Random misfire at high RPM, under load, or under random circumstances" calls for the inspection / correction of valve clearances in addition to checking the fuel pressure.

Just pull the EGR valve off and inspect it, make sure it isn't clogged or obstructed. However, when it's bad, it'll usually throw a code of its own.


Side note: Buy one of these http://www.helminc.com/helm/product2...C01&itemtype=N

 

okay cool thanks, ill check the valves and the fuel pressure in the morning when i can see .... i will also check the continuity of all the coils

thank you for the fast response

 

Just a quick FYI:

The fuel pressure should be 40 - 47 psi.


The clearance for the intake valves should be 0.18mm - 0.22mm (0.007 - 0.009 in.) and the exhaust valves should be 0.23mm - 0.27mm (0.009 - 0.011 in.)

 

everything checked out fine, the valves and the fuel pressure are in spec....

 

Did you check the injectors? The service manual says it's plugs, injectors, bad ECM/PCM, or a bad wire/connector causing a short/open.

There are 8 pages of diagnostics for these codes and nobody is gonna type all that so, get a service manual.

 

okay cool thanks