How JustAnswer Works:
  • Ask an Expert
    Experts are full of valuable knowledge and are ready to help with any question. Credentials confirmed by a Fortune 500 verification firm.
  • Get a Professional Answer
    Via email, text message, or notification as you wait on our site.
    Ask follow up questions if you need to.
  • 100% Satisfaction Guarantee
    Rate the answer you receive.
Ask -Brad- Your Own Question
-Brad-
-Brad-, Dodge Dealership Tech
Category: Dodge
Satisfied Customers: 6969
Experience:  16 Yrs Chrysler/Dodge Technician. ASE Master Certified(L-1)
10114124
Type Your Dodge Question Here...
-Brad- is online now
A new question is answered every 9 seconds

I have a 2007 dodge caliber throwing a p0304 misfire code

Customer Question

i have a 2007 dodge caliber throwing a p0304 misfire code the plugs are brand new the coil is firing the injector has power i didnt check for pulse but did a ohms test and test good compression is good what else would cause one cylinder to misfire only
JA: Have you seen the misfire code before? Has the car been stalling?
Customer: if you rev it up and let drop back down it does stall
JA: Are you fixing your Caliber yourself? What have you tried so far?
Customer: yes so far just what i told you about in the first message is there any sensors that will cut the pulse off to just one injector for some strange reason once started you can also smell the catalytic converter after a few minutes of running
JA: Anything else you want the mechanic to know before I connect you?
Customer: no
Submitted: 1 month ago.
Category: Dodge
Expert:  Cary York replied 1 month ago.

Hi, I’m Cary and I’ll be helping you today.
Please understand that I can't smell, hear, or touch the vehicle, so patience is appreciated. Before leaving the site make sure and leave me a rating. You can still reply to me as many times as needed, even after the rating..

Can you feel the engine misfiring.

Customer: replied 1 month ago.
you can feel it shake
Expert:  Cary York replied 1 month ago.

If you can smell the cat conv I would assume the injector is firing, dumping fuel into the cyl and in the exhaust.

Expert:  Cary York replied 1 month ago.

The sure way of course would be to check pulse.

Customer: replied 1 month ago.
if the coil is firing and you have fuel and the compression is good then what can cause a misfire
Expert:  Cary York replied 1 month ago.

The coil. You said it was firing. Did you remove the coil and leave it plugged in and check for spark that way?

Customer: replied 1 month ago.
i pulled it and put a plug in the end of it and started the car and watched the spark while running
Expert:  Cary York replied 1 month ago.

What size engine?

Customer: replied 1 month ago.
2.0 you can swap the plug and the coil around and the misfire only stays at cylinder 4
Expert:  Cary York replied 1 month ago.

A broken valve spring can cause a misfire and still have good compression spinning over at starter speed. I have seen this several times. I would remove the valve cover and inspect. It only pays 0.7 hours to R&R so it is not that hard. And the gasket is reusable.

Expert:  Cary York replied 1 month ago.

Remember if you rate me we can still continue the discussion.

Customer: replied 1 month ago.
i will check the valve spring should it be easy to tell once the cover is off or will it be hard to tell
Expert:  Cary York replied 1 month ago.

Yes it should. Just follow the coils of the spring from one end to the other. You may need a small mirror in some areas.

Expert:  Cary York replied 1 month ago.

Just remember. There are 4 valves/springs per cyl. Look at all 4 on the cyl.

Customer: replied 1 month ago.
well i pulled the valve cover gasket and had my son bump it over and all 4 valves seem to be coming back up the same height to make 100% sure i will have to remove the cams and the valve spring covers to see them fully but just from how they perform they seem to be okay
Expert:  Cary York replied 1 month ago.

I will open this up to another expert to see if the can help. I have to go. Thank you.

Expert:  -Brad- replied 1 month ago.

Good evening and welcome to JustAnswer!!

My name is ***** ***** I have worked for a Chrysler-Dodge-Jeep dealership for 19 years and I will do my best to help.

I will need for you to check the compression of cylinder #4 and tell me what you get..

Talk soon,

Brad

Customer: replied 1 month ago.
okay did a bunch of testing and checking the only thing i didnt do before is check the injector pulse so i put valve cover back on and all the coils back in unplug the injector check for pulse so i plug the injector back in it was running fine then after a few minutes the check engine light starts flashing and it running rough again so i check the pulse at that moment and no pulse is there a cam sensor or something that could be faulty shutting down the fuel pulse to # 4 cylinder
Expert:  -Brad- replied 1 month ago.

If you are 100% sure that your loosing injector pulse for cylinder #4 then swap #4 with #3 injectors and then tell e if the misfire moves to #3 cylinder(P0303)

Talk soon,

Brad

Customer: replied 1 month ago.
okay did it . it ran fine for a few minutes then came up cylinder #4 misfire again there is a tapping noise sounds like a loud injector could it possibly be a broken valve spring if so is it possible to take all the cam bolts and caps off without disturbing the timing and remove the spring caps to see or do you have another possible cause
Expert:  -Brad- replied 1 month ago.

Since the misfire is staying on #4 it is time to check the compression..

Customer: replied 1 month ago.
okay checked the compression it was 180 i let it sit for a hour and it didnt leak down at all
Expert:  -Brad- replied 1 month ago.

Good morning...

If you got 180 in cylinder #4 then I would need for you to test the other 3 because 180 is on the high side and you may have a camshaft issue.. This world engine doesn't have rocker arms but rather buckets. The camshaft will push down on the bucket and the bucket is on top of the valves.. Spin the engine over with the valvecover off(Disable the ASD relay) and see if the camshaft is pushing down the bucket as the rest. Here is the valve lash:

Valve Lash

Intake0.17 - 0.23 mm0.006 - 0.009 in.

Exhaust0.27 - 0.33 mm0.010 - 0.012 in.

Let me know your findings,

Brad

Customer: replied 1 month ago.
okay i will have to check the valve lash but the buckets all seem to be going up and down the same amount i watched them the other day when trying to see if there was a broken valve spring but according to alldata the compression should be from 170 to 225 on this engine
Expert:  -Brad- replied 1 month ago.

Yes you are correct the compression should be:

Compression Pressure1172 - 1551 kPa170 - 225 psi

The tapping your hearing is worrying me, can you tell if it's coming from in the head or outside the engine? If the PCM detects a misfire it will kill the injector to that cylinder...

Customer: replied 1 month ago.
it is really hard to tell it sounds like outside but if you put your head near the 3rd and 4th cylinder it sounds like it could be coming from the inside near the intake valves
Customer: replied 1 month ago.
okay checked all of them and the biggest i could fit for intake on all cylinders was .008 and intake .014