P0307 help..
Thread Starter
Racer
Joined: Jun 2012
Posts: 288
Likes: 0
P0307 help..
Hi guys,
I have had my car for around 6 months now and have always had a slight misfire. Well, have replaced plugs, wires, removed my cats, cleaned the TB, cleaned the MAF, replaced both front o2 sensors, and have ran cleaner through the injector's as well. Also replaced or installed however you want to say it the intake gaskets with new ones. I have also checked to make sure I had no broken or cracked springs, and that the fuel pressure was where it needs to be.
What could be causing the misfire now??? She idles fine, but you can hear and see the misfire. And if you give gas she will still misfire, just not as badly. Upon giving just a tad more gas she will buck and complain. BUT if you give it enough to get past that point she will clear up and run great. Just doesnt seem as powerful as she was only a couple weeks ago after some other stuff i did. Also I have noticed that as soon as I cut off the car i can hear a quite hiss coming from the passenger side engine compartment. Thought this may be the intake gasket, so i replaced those and problem got better, but is still there and I can still hear the hiss.
Any ideas? I posted alot of info I know, but figure doing so will help you guys help me. Thanks to all who help!!
I have had my car for around 6 months now and have always had a slight misfire. Well, have replaced plugs, wires, removed my cats, cleaned the TB, cleaned the MAF, replaced both front o2 sensors, and have ran cleaner through the injector's as well. Also replaced or installed however you want to say it the intake gaskets with new ones. I have also checked to make sure I had no broken or cracked springs, and that the fuel pressure was where it needs to be.
What could be causing the misfire now??? She idles fine, but you can hear and see the misfire. And if you give gas she will still misfire, just not as badly. Upon giving just a tad more gas she will buck and complain. BUT if you give it enough to get past that point she will clear up and run great. Just doesnt seem as powerful as she was only a couple weeks ago after some other stuff i did. Also I have noticed that as soon as I cut off the car i can hear a quite hiss coming from the passenger side engine compartment. Thought this may be the intake gasket, so i replaced those and problem got better, but is still there and I can still hear the hiss.
Any ideas? I posted alot of info I know, but figure doing so will help you guys help me. Thanks to all who help!!
Thread Starter
Racer
Joined: Jun 2012
Posts: 288
Likes: 0
BTW, took it to the dealer and he is the one who told me it was a p0307 code, the car throws NO codes at all. It may store them in some background area i dunno...But as far as what shows up on the dash, nothing.
Le Mans Master
Joined: Mar 2004
Posts: 8,700
Likes: 298
From: Ft. Lauderdale Fl
Might be I'm a little dyslexic...like being a little pregnent but couldn't find what you drive or how many miles? Could it be a dirty fuel filter?
Crap gas from the same station? Need to do a compression test?
Fill out the information (view public profile) so we know more about you and your ride.
Crap gas from the same station? Need to do a compression test?
Fill out the information (view public profile) so we know more about you and your ride.
Last edited by runner140*; Dec 14, 2012 at 07:23 AM. Reason: add
Team Owner
Joined: Mar 1999
Posts: 22,025
Likes: 192
From: At the beach in little Rhody
#7 is also the one that will typically fail the piston as well. Do a compression or better yet leak down test. I wouldn't throw any more money at it until you establish the mechanical aspects are OK.
Thread Starter
Racer
Joined: Jun 2012
Posts: 288
Likes: 0
Ok thanks guys, she is a 2000 c5 auto, with 198k on her. I have done a comp test a little while back and she came out with flying colors! cant remember the exact numbers, but all were well within 7psi or so of each other and all over 140 psi or so.
One thing, I changed out the plugs again today and she got a decent bit better. But then again, she did last time I changed the plugs too. using tr55's and she runs like a scalded dog for a little while until once again she starts missing. Sorry guys, i work third shift and am drained right now, and have 9 more hours before i get off work. Just not in the best of mind remember everything. Sorry..
One thing, I changed out the plugs again today and she got a decent bit better. But then again, she did last time I changed the plugs too. using tr55's and she runs like a scalded dog for a little while until once again she starts missing. Sorry guys, i work third shift and am drained right now, and have 9 more hours before i get off work. Just not in the best of mind remember everything. Sorry..
Thread Starter
Racer
Joined: Jun 2012
Posts: 288
Likes: 0
Just removed the #7 spark plug, it is bleech white but has no other use shown on it at all. The base is a sooty color which is good I do know, but the porcelin being white, as in whiter than new, would mean she's running lean would it not?
And running lean besides being horrible for the engine, would cause a misfire as well. BUT would the injector be the cause of this? Tomorrow i will swap the injector's from #7 and #1 to see if the issue follows. But anyone else have any other info? Or is this normal and my misfire coming from elsewhere?
And running lean besides being horrible for the engine, would cause a misfire as well. BUT would the injector be the cause of this? Tomorrow i will swap the injector's from #7 and #1 to see if the issue follows. But anyone else have any other info? Or is this normal and my misfire coming from elsewhere?
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Safety Car
Joined: Aug 2011
Posts: 4,450
Likes: 410
From: Portland OR
Compare # 7 with a few others. They run awful white in these engines.
Swaping injectors is an excellent idea.
Doubt it would be a head gasket leak. Burning DexCool will make the plug look funny.
With those miles, a leakdown test is also a good idea.
Ron
Swaping injectors is an excellent idea.
Doubt it would be a head gasket leak. Burning DexCool will make the plug look funny.
With those miles, a leakdown test is also a good idea.
Ron
Thread Starter
Racer
Joined: Jun 2012
Posts: 288
Likes: 0
Well, she doesnt smoke, doesnt use oil or antifreeze at all, and I have not done a leak down test yet, just compression test. So I'll give that a go and see what happens. Thank you all for your input.
One thing, when its rainy and cold out, the car seems to run better, dunno why. Very weird I know. Problem is I barely give it any gas and she will kinda sputter a very small bit. But if I give it more gas going down the road she will then straighten up and fly right. Besides of course the miss at idle.
I will get that injector switched today. The little ring around injector base, not the seal but the other one..that is broken on several of my injectors. I think its just a spacer though. Would that be causing all this? I noticed this while replacing the intake gaskets.
One thing, when its rainy and cold out, the car seems to run better, dunno why. Very weird I know. Problem is I barely give it any gas and she will kinda sputter a very small bit. But if I give it more gas going down the road she will then straighten up and fly right. Besides of course the miss at idle.
I will get that injector switched today. The little ring around injector base, not the seal but the other one..that is broken on several of my injectors. I think its just a spacer though. Would that be causing all this? I noticed this while replacing the intake gaskets.
