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Dan
Dan, ASE Certified Technician
Category: Honda
Satisfied Customers: 1644
Experience:  Auto Technician
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I have a 2005 Honda Civic si. I get the p0302, 304, 300

Customer Question

I have a 2005 Honda Civic si. I get the p0302, 304, 300 series codes. I put in new ngk plugs and new after market coil packs. I still get the same codes, hesitation on take off and sometimes it dies on take off. I get only 330 miles to a tank of gas. I need help.
JA: Do you happen to have a code reader or scan tool? What size is your engine?
Customer: It is the 2.0 liter ve tech. The code reading was done at autozone and my mechanic. The check engine light is on, that is why I had the codes read
JA: Are you hoping to fix this yourself?
Customer: I can take it to my mechanic if I can figure out the problem, because he can't
JA: Is there anything else the Honda Mechanic should be aware of about your Honda?
Customer: It has 159000 miles. New plugs, new paks, new air filter. It is fuel injected and I thought the egr valve needed to be cleaned, but Honda dealer ship doesn't think the 2005 si hatchback has an egr valve
JA: OK. Got it. I'm sending you to a secure page on JustAnswer so you can place the $5 fully-refundable deposit now. While you're filling out that form, I'll tell the Honda Mechanic about your situation and then connect you two.
Submitted: 10 months ago.
Category: Honda
Expert:  Gary replied 10 months ago.

if the codes are cleared which ones reset first ?

how often will it run bad like this ?

Customer: replied 10 months ago.
P0302, p0300. Runs worse when low on gas or cool days. Have to warm it up completely or it will die when I back into the yard
Expert:  Gary replied 10 months ago.

if you swap # ***** fuel injector with # ***** fuel injector will it set a 303 code after you clear the codes ?

Customer: replied 10 months ago.
I have never swapped injectors. Do you think bad injectors could cause bad gas mileage? I tried injector cleaner
Customer: replied 10 months ago.
I only run 93 or 89 octane
Expert:  Gary replied 10 months ago.

it could

since the code is specific to # ***** cylinder ( the 302 code ) and new plugs and coils did not fix it the issue comes down to a fuel injector issue or possibly compression problem for # ***** cylinder

if you have any questions please ask as i do not get credit for my work until you rate us here at Justanswer

Customer: replied 10 months ago.
I get the 304, 303, 301 codes also in addition to 300 code random misfires
Expert:  Gary replied 10 months ago.

ok if its setting all 4 cylinder misfire codes check the fuel pressure if the fuel pressure is good try a new crank sensor

if you have any questions please ask as i do not get credit for my work until you rate us here at Justanswer

Customer: replied 10 months ago.
If the fuel pressure is bad, do I need a new fuel pump? Where would the crank sensor be on this car?
Expert:  Gary replied 10 months ago.

yes if the fuel pressure is low or bad it will need a fuel pump

the crank sensor is behind the plastic timing cover

near the crank bottom timing belt gear

if you have any questions please ask as i do not get credit for my work until you rate us here at Justanswer

Customer: replied 10 months ago.
Could it be the timing belt? My Honda Fit would also would die if you did not warm it up a while when you backed up. Where is the fuel pump?
Expert:  Gary replied 10 months ago.

the fuel pump is in the fuel tank

checking compression will tell you if the timing belt has jumped or has play in it

if all 4 cylinders are low compression then usually the timing belt is the issue

if you have any questions please ask as i do not get credit for my work until you rate us here at Justanswer

Customer: replied 10 months ago.
Hello. Me again. I want to rate your service. I followed your advice. The car gets 230 miles to a tank. New plugs now, new Denso coil packs, and new oem fuel pump. Still hesitates on take off, misses when I start up, and the 2005 Honda Civic si hatchback has a timing chain. Still getting po302, 301, and 300 codes
Expert:  Gary replied 10 months ago.

still sets those codes all 3 ?

Customer: replied 10 months ago.
What are you asking? I get random misfires and it is throwing 300, 301, 302, 303, 304 randomly. The check engine light went out for shot 5 miles when I put in the new fuel pump, then came back on with all these codes
Customer: replied 10 months ago.
That is it went out for about 5 miles. Still misses on start up and take off. Is there another fuel filter somewhere?
Customer: replied 10 months ago.
I can't find an egr valve on it, and local Honda dealership claims it doesn't have one
Expert:  Gary replied 10 months ago.

ok now i understand

there is only one that is built into the fuel tank fuel pump

yes some did not use EGR valves

with a new fuel pump and this model does not have an EGR valve can you do a compression test on all 4 cylinders ?

Customer: replied 10 months ago.
That cost $50. With it miss firing randomly on all 4 cylinders wouldn't that be pointless. It is something making all 4 miss. When I slow down, being a 5 speed Manuel, the rpms drop to about 400 and then come back up
Expert:  Dan replied 10 months ago.

New expert here, I am Dan ASE master tech.

You need to hook it up to a scan tool that can read live misfire data. You then need to determine why you have a misfire. Check spark, fuel, compression. You could even do a leak down test on the cylinders which is better and will tell you exactly where compression is leaking from. Have you checked your IAC valve? and have you cleaned the thottle body and mass air sensor? A dirty maf or IAC will cause idle problems.

Aftermarket coil packs are not the most reliable part.

Focus on cylinders one and two, which are towards the front of the engine. Check injector pulse on these, you can use a 194 bulb to make a noid light if you do not own a set.

If you need more help, use the reply tab to continue our conversation. If no further assistance is needed, kindly rate my service. You can rate at any time and we can continue to work on your question, this does not close out your question. Remember, in some cases it can be difficult to completely diagnose or help repair your vehicle without being there, but I try to give you the best possible answer with the information that I have.

Thanks Dan

Customer: replied 10 months ago.
I put on a new air filter. What is a maf and what is a IAC valve? Whole words please
Customer: replied 10 months ago.
This has Denso oem coil packs on it now. Not after market
Expert:  Dan replied 10 months ago.

Mass air flow sensor and Idle air control valve.

Customer: replied 10 months ago.
Can these be replaced or do they need to be cleaned?
Expert:  Dan replied 10 months ago.

Clean first, also clean the thottle body