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Bumpy Engine Idle, and CEL code P0305

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Brian L

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Discussion starter · #1 ·
I've had this issue for over a year, and I've just kind of accepted it and kept going, but now I'd like to see if there's a way to fix it. First off, I've had CEL code P0305 for a long time, which is a misfire in cylinder 5. I never really believed it because there was no decrease in engine power, and no hesitation, but every time I reset the computer, the light will come back on in a couple days with the same code. I've changed the spark plugs, run fuel injector cleaner through the gas a bunch of times, run Sea Foam through the Throttle Body and gas tank, and still get this CEL.

Another symptom, which might be related, is that if I roll forward at idle, like moving up at a red light, I get this kind of bumpy, up and down, slightly jerky idle. Once I'm on the gas, everything is fine.

So, I guess my question is: Are these two related, and how do I fix them?

BTW....I've pulled the spark plug since replacing it, and it's kind of whitish, so I at least know that it's firing. Not sure if it's getting fuel, though.


Thanks,
Brian
 
#2 ·
You may have a bad plug wire or a bad injector. Exchange the injector on the #5 cylinder with another one of you injectors and see if the code follows that injector. That will help narrow down the possibilities.
 
#3 ·
http://www.aa1car.com/library/reading_spark_plugs.jpg

Plugs are not supposed to be white. This is a symptom of it being too hot. It's either not the right plug, you have a manifold leak or your fuel is too lean. Check the other plugs, check your fuel rail for pressure. Check and clean the IAC and TPS. And please...i know people swear up and down that there is no problem with the plat plugs but....try using copper first. Also remember....use anti-sieze.
 
Discussion starter · #4 ·
bwdakrt said:
Exchange the injector on the #5 cylinder with another one of you injectors and see if the code follows that injector. That will help narrow down the possibilities.
Click to expand...
Are the injectors as easy to pull as it sounds? I recall thinking about messing with it one time, until I noticed that you have to pull the whole fuel rail or something. I remember them being hard to get to for some reason. I'll take another look at it this weekend. Thanks!
 
Discussion starter · #5 ·
flyboy121785 said:
http://www.aa1car.com/library/reading_spark_plugs.jpg

Plugs are not supposed to be white.
Click to expand...
I understand that, but at least I know it's firing. It's probably classified as the "too hot" category, which probably just means it's firing and not getting fuel. Amazing, though, that when I take it to Dodge to have them look, all they can come up with is that I must need new plugs. They're absolutely no help. And they charge $108 to run the diagnostic, when I can tell them what codes are there already.

Brian
 
#6 ·
Brian L said:
I understand that, but at least I know it's firing. It's probably classified as the "too hot" category, which probably just means it's firing and not getting fuel. Amazing, though, that when I take it to Dodge to have them look, all they can come up with is that I must need new plugs. They're absolutely no help. And they charge $108 to run the diagnostic, when I can tell them what codes are there already.

Brian
Click to expand...
Yay stealership! :clap2:
 
#7 ·
Hi BrianL,

did you finally get rid of your p3050-problem? I'm bothered with the same symptoms since a week. Replaced wire and spark, but still stupid code and softly bumpy engine when ideling..

Hope to get help

Merry Xmas

Januwar
 
Discussion starter · #8 ·
Sadly enough, I've lived with this issue for about two years now, with no solutions. Every so often, the light goes off, only to come back on a few days later. I've run fuel injection cleaner through several times, replaced spark plugs, switched the coil pack with another cylinder, cleaned the throttle body, all to come back to the same CEL. I'm up to 175,000 miles, and have just come to live with it, although I sure would like to know what the real issue is. I have to leave the A/C on when at a stop light, or the idle is so bad that it almost dies out. Please let me know if you come up with a solution. I'm going to try to make 300,000 miles.

Merry Christmas!

Thanks,
Brian
 
#9 ·
Hi again,

well fortunately my Dodge seemed to have healed himself. Light has gone and bumpy ideling too. I have just one idea what could have been the reason, maybe it helps you too:
The problem started after having filled up the tank on a very cold day. SO I guess maybe the gaz-bucket did not close perfectly and some air came into the system. After having cleaned all rubber-parts of the fuel door and filling up the tank again the engine began to rum smoother and smoother until the point where -just some hours ago- the light went off.
Maybe something is wrong with your gas cap?

Hope you can solve the problem soon

MAny thanks
 
Discussion starter · #10 ·
A vacuum seal could be my problem, but the CEL is always for cylinder #5, no matter what I do. That leads me to believe there is something specifically wrong with that cylinder. I guess I should replace the fuel injector, but that's probably easier said than done, and I'll get robbed by a shop if I have them do it. Plus, they probably have to replace all of them, not just one.

We'll see. I hope your symptoms don't come back.
 
#11 ·
Brian L said:
A vacuum seal could be my problem, but the CEL is always for cylinder #5, no matter what I do. That leads me to believe there is something specifically wrong with that cylinder. I guess I should replace the fuel injector, but that's probably easier said than done, and I'll get robbed by a shop if I have them do it. Plus, they probably have to replace all of them, not just one.

We'll see. I hope your symptoms don't come back.
Click to expand...
Try replacing the 0-rings on the #5 injector and see if that helps.
 
#13 ·
@BrianL:
I'm no mechanician, but as well my dodge had a problem in zyl 5. Maybe it strikes the "weakest" injector if something is wrong with the fuel-pressure.. don't know, but would give it a try. Renew the seals or the cab and I keep my fingers crossed for both of us

Cheers
 
Discussion starter · #14 ·
Well, I finally built up the courage to replace the fuel injector on cylinder #5. The project was more of a pain-in-the-a** than I would have liked, but I got it done. A couple other O-rings fell off while I fumbled around with the fuel rail, so I replaced those also. Getting the fuel rail back on the injectors was quite a pain. Anyhow, it started much quicker than usual, which was nice, and it idled a lot better without any A/C running than it used to. The CEL was also off (probably just from disconnecting the battery terminal). So, things were good for about 20 miles, when the CEL came back on. What do you know....it's the same code, P0305. My idle got worse and worse after a couple days, and now it's pretty much back to where it was. I also have noticed a gas/exhaust type of smell in the car now, after letting it warm up in the morning with the heat going, and then getting. I wouldn't really worry about that too much, except that I drop my one year old off at daycare every morning in this car. That can't be too good for her little brain.

So, I don't know what the heck is going on with this thing, but it's getting closer to making a trip to the dump.


Brian
 
#15 ·
Hi Brian,
I'm so sorry to read your news. What could be worse then working your a.. off and then in the end get that stupid light going on again.
About the smell you describe, is it more like gazoline or emissions (sulfur-like taste)?
My light goes on every now and then. Approx. every 4 day engine runs not that smooth (mot as in you case where it is really bumpy). Shortly after light will appear. But what is funny is that in the moments light shows off, engine runs smooth again. So I reset the light and wait for the next "surprise".
I think it's time to ask some guys @Dodge. Isn't there any helpline or chat or real Dodge-professional board?

Take care of you and your child, keep window open while driving

Januwar
 
#16 ·
Me again,

did you every try to clean the valves from carbon, as described here:

Another important step of any tune-up is to remove carbon build-up, especially if the vehicle is typically only driven short distances at low speeds. Carbon build up can cause burnt valves, pre-mature wear on valve seals, oil burning, loss of compression/power and hot spots on piston heads. A simple, non invasive method to accomplish this is by steam cleaning. With the engine at operating temperature, open the air cleaner to access the intake. Grab a 16-20 ounce bottle of water and remove the cap and hold your thumb over the opening. Increase engine speed to about 2,000 RPM, by moving the throttle linkage. Slowly, and I mean slowly, drizzle water into the intake. The engine will start to bog down. Stop the water and maintain the idle speed, until it picks back up. Repeat this process until the bottle is empty. Then, after closing the breather, take the vehicle out on the road and drive it a few miles. Hit the highway, if at all possible. This will insure that all the moisture and loosened carbon deposits are removed. You could also treat your gas and engine oil with zMax or Lucas micro-lubricants to remove and prevent carbon buildup.

Found this in other board and some say it helps..

Cheers
 
#18 · (Edited)
Brian L said:
I've had this issue for over a year, and I've just kind of accepted it and kept going, but now I'd like to see if there's a way to fix it. First off, I've had CEL code P0305 for a long time, which is a misfire in cylinder 5. I never really believed it because there was no decrease in engine power, and no hesitation, but every time I reset the computer, the light will come back on in a couple days with the same code. I've changed the spark plugs, run fuel injector cleaner through the gas a bunch of times, run Sea Foam through the Throttle Body and gas tank, and still get this CEL.

Another symptom, which might be related, is that if I roll forward at idle, like moving up at a red light, I get this kind of bumpy, up and down, slightly jerky idle. Once I'm on the gas, everything is fine.

So, I guess my question is: Are these two related, and how do I fix them?

BTW....I've pulled the spark plug since replacing it, and it's kind of whitish, so I at least know that it's firing. Not sure if it's getting fuel, though.


Thanks,
Brian
Click to expand...

Brian L.,

Just found your article regarding your issue. Currently I'm having the same problem with my 01' Durango 4.7 liter V-8 which gives me the same code/P0305 and all the other symptoms you described.

This past saturday I had a chance to take it to the dealership for a look see and for the price I paid $102 they gave me nothing in return except that my no 5 cylinder has low compression and that something bad is happening inside my engine. I'm now taking it to another mechanic for a second opinion and because I only have 85K on my odometer I refuse to allow them to hint of an engine re-build especially since this dealeship has had all my service usiness pretty much since bought new.

For my sake I hope it's only my ejectors, gas cap or something like that and not an engine re-build. If anything on your end comes up please let me know what you find. Perhaps I can pass that along to the new mechanic I visit.

rimfire,22:wave:
 
Discussion starter · #19 ·
Thanks for the post, rimfire. I'm up to 190,000 miles now, and never found out what the problem was. The CEL is still on, and I still have the same symptoms. I don't even remember how long it's been now; probably 3 years. I just live with it, and always have some form of A/C running, even if it's just the defroster in the winter, so that my RPMs are up just enough to have a smoother idle at red lights.

Since my last post, I had a mechanic do a compression test on #5, and he said it was fine. He just did it for free for me, since I agreed to allow him to do a spark plug tune-up for me. He said he'd have to charge the full $100 or so to do a full-on diagnostic, and I said "no thank you." I've already tried enough, and I didn't think he'd find anything. Don't let them talk you into something crazy. I've lived with this for a long time. I'm just enjoying not having a car payment and saving up a ton of cash to buy a new car one day when this thing quits.

I also had him replace my radiator because my engine would run hot when under a strong load, but that's unrelated; the little tubes get caked up after a while, and not enough coolant can push through when you're hard on the gas.

I just realized I never replied to januwar earlier. I never tried the bottle of water idea, but I did the same thing with sea foam, and didn't get much results other than some white smoke burning out the exhaust for a little.

Let me know what you find out. I'd still like to know what the deal is. I've been meaning to search for a vacuum leak by taking a can of carb cleaner and going around spraying it on hoses and stuff to see if I get any surge in RPMs while the engine is running. I figure that would let me know if there was a leak at that spot. I'll get around to that one day when the two little ones aren't screaming about something.

Brian
 
#20 · (Edited)
Brian L,

Yeah my visit to the new mechanic is this coming Saturday. According to the dealership they told me that the no 5 cylinder is low on compression and that's why the computer sent the code.

I don't know if the mechanic/dealership checked for any vacum leaks of any sort but again I did notice that when I drove it off the lot the engine was running fine and they reset the CEL for me. It ran fine for about 50 miles and then drove home and allowing it to sit for about 3-4 hours before heading out to dinner. It was then allowing the engine to idle for about 30 seconds the issue started all over again. The CEL light came on again and the engine begain to idle roughly.

What bogs my mind is what they did after they did the compression test. They said nothing if the spark plug was dry white looking or wet with oil. They just said compression was not too good. I did notice though the dash guage was showing slight low oil pressure though but no numbers as that how the dial is.

If the cylinder was holding pressure then WHY did it run so well for 50 miles and then go down hill so fast when I got home????

Is it a coil pack??? I don't think so now. Is it an injector??? Perhaps as I never had to change any of these since bought new. Could it be something like the TPS sensor???? Perhaps cuz I don't think it's ever been changed before. Can it be my gas cap??? Perhaps cuz I've been using the origional gas cap since bought new. Pretty much every part is origional since bought new except for things like spark plugs and such.

What I do know and can tell you is that I had them do a lube oil and filter change for me and as always I add a bottle of gas additive "Gumout/Regain" to the tank and then one week later this issue began. I always add a bottle every 3K as a preventative maintenance. Can this have anything to do with it???

Wish me luck as I hope this mechanic can find ou what the problem is and return to me a report that my pistol rings didn't go south on me!!! Two or three hundred bucks for repair is OK with me but to have my engine re-built all because of 1 piston ring is messed up.

Is my truck really old compared to you others??? I only have 85K on the odometer and it's ten years old. I admit.


Thanks again everyone. I now know that P0305 code can be due to allot of things other than low pisto compression. Still though I'm scared that it is partly due to bad piston rings.


rimfire,22
 
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