Misfire Code? Car Shaking
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Joined: Jun 2005
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From: Austin TX
Misfire Code? Car Shaking
I'm currently throwing a 0300 code and the car shaking just a little at idle. Idle is also a hair rough. Is that a misfire code?
It started when I tried to shift from 3-4 and accidently went into 2nd. I checked the pushrods and replaced 1 bent one (ony slightly bent).
I'm gonna swap stock spark plugs for NGK TR 6s tonight in hopes that I may have just damaged a spark plug during longtube install. Are these pregapped?
Most recent mod was longtubes w/ off-road pipe. I haven't gotten 02s turned off yet? Could this also cause the shake? Maybe an exhaust leak, I hear a little ticking?
My only other mods are intake and granatelli maf.
Is there anything else that I should direct my attention to that may be causing the misfire? Is there anything else that could cause this?
Thanks in advance.
It started when I tried to shift from 3-4 and accidently went into 2nd. I checked the pushrods and replaced 1 bent one (ony slightly bent).
I'm gonna swap stock spark plugs for NGK TR 6s tonight in hopes that I may have just damaged a spark plug during longtube install. Are these pregapped?
Most recent mod was longtubes w/ off-road pipe. I haven't gotten 02s turned off yet? Could this also cause the shake? Maybe an exhaust leak, I hear a little ticking?
My only other mods are intake and granatelli maf.
Is there anything else that I should direct my attention to that may be causing the misfire? Is there anything else that could cause this?
Thanks in advance.
Intermediate
Joined: May 2005
Posts: 37
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i too am throwing this code except on a 98 A4. i have replaced plugs and wires, takin it to a shop for a total of 3 times to name a few things to remidy this condition... nothing yet. I noticed this condition after i added electronic cut outs. Not only does it idle bad but it is hard starting and smells of raw fuel(only on pass. side). runs like a S-O-B though! oh and maybe i should add that since it has had this condition it has eaten 3 starters. it is currently in another shop now so if i find anything i will let you know.
Ethan
Ethan
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From: Austin TX
Once we got the plugs changed, I went to double check the torque on the header bolts. Turns out each bolt had at least a turn and a half on it easily. Some bolts had about 5-10 turns, but every bolt was not thightened down. Set the bolts to 47 ft-lbs. One bolt must have been messed up because it broke. But it was the center bold where two bolts are directly beside eachother. Something I'm not gonna worry about for now. Reassembled everything and added some easy seal band clamps to the collector/x-pipe fitting and started her up.
This definately cleared my misfire code. Wether it was a connection, or an exhaust leak, I'll never know. But they're both fixed for now.
It still feels like the idle is just a hair off, and the car still shakes, but just a little. This will probably be fixed when I get the cam in and get my rear 02s turned off via dyno tuning.
This definately cleared my misfire code. Wether it was a connection, or an exhaust leak, I'll never know. But they're both fixed for now.
It still feels like the idle is just a hair off, and the car still shakes, but just a little. This will probably be fixed when I get the cam in and get my rear 02s turned off via dyno tuning.
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From: Austin TX
On the way home yesterday the damn code came back. Still throwing a misfire. I went to a local parts store and picked up some Borg-Warner spark plug wires. Let the engine cool and started changing them. On the driver side second from front, I pulled the wire off the coil and went to remove it from the spark plug when the wire completely severed at the boot. I think this may have been the problem as I drove it quite a bit last night and the code hasn't come back. 
Racer
Joined: Oct 2001
Posts: 483
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From: Downingtown PA
If you're running long tube headers, you're going to need (sooner or later) a set of boot protectors. Koolsox is the best known brand. The no. 7 wire (driver's side closest to firewall) tends to burn up pretty quick without them.
Team Owner
Joined: Sep 2001
Posts: 23,283
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From: Lake Elsinore, CA
You do know that factory spec on the exhaust manifold (header) bolts is 11 lb. ft. first pass and 18 lb. ft. final pass, right? If you need a torque spec sheet for the C5, I can email you one.
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From: Austin TX
Hmmmm.... The instructions said 47 ft-lbs. I'd appreciate it if you would e-mail that to me. The code is back too. 
I'm going to see how #7 wire is and maybe get a boot protector for it. Also going to install a 160 thermostat and get some programming done. Just to rule out all posibilities I'm going to replace driver side header gasket too.
I HATE MISFIRE CODES!
I'm going to see how #7 wire is and maybe get a boot protector for it. Also going to install a 160 thermostat and get some programming done. Just to rule out all posibilities I'm going to replace driver side header gasket too.I HATE MISFIRE CODES!
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Drifting
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From: Stealth So Cal GOCC ...comming to invade your neighborhood soon
You said you bent a pushrod after an over rev? Did you a compression and leakdown test? How do you know that you didn't bend a valve...especially if it's ticking? If the pushrod got bent then it maxed out something...spring....valve to piston top?
I thought that you had to pull the heads to remove the retainers to replace the pushrods. I hope you pulled the valves at that time. Are the rockers allright?
I thought that you had to pull the heads to remove the retainers to replace the pushrods. I hope you pulled the valves at that time. Are the rockers allright?
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Joined: Jun 2005
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From: Austin TX
Yes, just installed headers.
Xtreme, I don't know that I didn't bend a valve, but since the misfire is not continous, I don't believe that I did. Misfire only occurs at time of start up and during idle which is still kinda rough. The pushrod that was bent was only slightly bent. Also, the ticking sounds like any exhaust leak I've ever heard.
For the pushrods, I only had to remove the valvecover and rockers. Rockers look fine.
I'm also throwing some BFO codes. At this point, my hypothesis is that since the headers were very loose at the time of over-rev, I believe that I may have destroyed part of the gasket. I am going to replace it for 8 bucks just to make sure. I think the BFO codes are being caused by the stock battery, which may also be the source of the misfire. I have an optima ready to go in.
Xtreme, I don't know that I didn't bend a valve, but since the misfire is not continous, I don't believe that I did. Misfire only occurs at time of start up and during idle which is still kinda rough. The pushrod that was bent was only slightly bent. Also, the ticking sounds like any exhaust leak I've ever heard.
For the pushrods, I only had to remove the valvecover and rockers. Rockers look fine.
I'm also throwing some BFO codes. At this point, my hypothesis is that since the headers were very loose at the time of over-rev, I believe that I may have destroyed part of the gasket. I am going to replace it for 8 bucks just to make sure. I think the BFO codes are being caused by the stock battery, which may also be the source of the misfire. I have an optima ready to go in.
