Intermittent Misfire
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- OG (First 100 Outposters!)
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Re: Intermittent Misfire
Changed both the coil and plug.
Still get P305 code at low RPM every now and then
Still get P305 code at low RPM every now and then
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY (sold)
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
- 32wildbilly
- Never gonna run around and desert you
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Re: Intermittent Misfire
What did the old plug look like when removed. Just dirty or oil fouled or carbon bridged?
Never gonna make you cry...
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- OG (First 100 Outposters!)
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Re: Intermittent Misfire
Just a bit dirty, a little cooked. Ill post a pic in a bit32wildbilly wrote: ↑Thu Jun 16, 2022 4:22 amWhat did the old plug look like when removed. Just dirty or oil fouled or carbon bridged?
Someone suggested it might be an injector issue. I'll run a bottle of techron or seafoam through
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY (sold)
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
- 02TX996Cab
- NG (Second 100 Outposters!)
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Re: Intermittent Misfire
Google tells me injectors or MAF are also potential sources of intermittent misfire. As you suggested, add a bottle of Techron (I'm partial to that, which may or may not be due to my having worked for Chevron for nearly 40 years) or Seafoam at your next fill-up. Also get some MAF cleaner and give your MAF a good spray-down. Those are both easy, inexpensive "zero regrets" fixes.
Proud owner of a Flat6-powered 2002 996 Cab, 2016 GT4, 2019 Ford F-150 "Country Cadillac", and 2005 Ford Focus (not so hot hatch) daily driver. And a Wright ZTO 52" to keep several acres of grass-like substance neat and tidy!
- FRUNKenstein
- Curator Extraordinaire
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Re: Intermittent Misfire
Jeez, I can't believe no one has offered the ultimate solution, but a guy I used to know over on Rennlist (dammit) swears by this stuff:
www.kansascityautomuseum.com
Current:
2002 996TT X50, Guards Red
1987 928S4, Guards Red
1987 951, Guards Red
1973 914 2.0 Bahia Red
2006 955S, Lapis Blue
Other toys:
1988 BMW 325i Cabriolet, Alpin Weiss
1987 Bertone X1/9, Verde Chiaro
Gone but not forgotten: 1975 914 2.0, Laguna Blue; 1999 996 C4 Aerokit Black; 1990 964 C2 Guards Red; 2006 955S Arctic Silver
Current:
2002 996TT X50, Guards Red
1987 928S4, Guards Red
1987 951, Guards Red
1973 914 2.0 Bahia Red
2006 955S, Lapis Blue
Other toys:
1988 BMW 325i Cabriolet, Alpin Weiss
1987 Bertone X1/9, Verde Chiaro
Gone but not forgotten: 1975 914 2.0, Laguna Blue; 1999 996 C4 Aerokit Black; 1990 964 C2 Guards Red; 2006 955S Arctic Silver
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- OG (First 100 Outposters!)
- Posts: 391
- Joined: Sat Jan 27, 2018 10:22 am
- Location: Austin (Lago Vista) and the Desert
Re: Intermittent Misfire
I dumped a bottle of Redline SL-1 fuel system cleaner in the tank. Need to drive it a bit and see02TX996Cab wrote: ↑Thu Jun 16, 2022 9:37 am Google tells me injectors or MAF are also potential sources of intermittent misfire. As you suggested, add a bottle of Techron (I'm partial to that, which may or may not be due to my having worked for Chevron for nearly 40 years) or Seafoam at your next fill-up. Also get some MAF cleaner and give your MAF a good spray-down. Those are both easy, inexpensive "zero regrets" fixes.
Where in TX are you?
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY (sold)
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
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- NG (Second 100 Outposters!)
- Posts: 343
- Joined: Thu Jun 07, 2018 9:33 am
- Location: Central Mass
Re: Intermittent Misfire
Supposedly these misfires can also be triggered by an intake lifter getting stuck on full stroke when it should be on short stroke. These 2-piece intake lifters are really devil's spawn.
Re: Intermittent Misfire
Heh. Along these lines - I was squirting some spray lubricant into the cylinders of the race engine I've been sitting on for 3+ years...and the goddamn straw shot off of the spray can, through the spark plug hole, and into the bore. *sigh*
Now I need to take a borescope and a part grabber up to Big Bear with me so I can get the straw out...
Now I need to take a borescope and a part grabber up to Big Bear with me so I can get the straw out...
FRUNKenstein wrote: ↑Thu Jun 16, 2022 11:48 am Jeez, I can't believe no one has offered the ultimate solution, but a guy I used to know over on Rennlist (dammit) swears by this stuff:
WD-40-Flexible-Automotive-1.gif
Understeer: You will hit the wall with the front end.
Oversteer: You will hit the wall with the rear end.
Horsepower: How hard you will hit the wall.
Torque: How far you will move the wall.
Gone hunting with Alec Baldwin and Dick Cheney. Back soon.
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- OG (First 100 Outposters!)
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- Joined: Sat Jan 27, 2018 10:22 am
- Location: Austin (Lago Vista) and the Desert
Re: Intermittent Misfire
JayG wrote: ↑Thu Jun 16, 2022 6:26 amJust a bit dirty, a little cooked. Ill post a pic in a bit32wildbilly wrote: ↑Thu Jun 16, 2022 4:22 am
What did the old plug look like when removed. Just dirty or oil fouled or carbon bridged?
Someone suggested it might be an injector issue. I'll run a bottle of techron or seafoam through
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY (sold)
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
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- OG (First 100 Outposters!)
- Posts: 391
- Joined: Sat Jan 27, 2018 10:22 am
- Location: Austin (Lago Vista) and the Desert
Re: Intermittent Misfire
So after running 2 bottles of Redline Sl-1 fuel system cleaner and a bottle of Royal Purple Max-Clean Fuel System Cleaner no codes for a day with freeway and city stop and go driving.
The codes were only at idle and (knock on wood) after the cleanse, no issue
will see what today brings.....
The codes were only at idle and (knock on wood) after the cleanse, no issue
will see what today brings.....
2004 Boxster S 6 speed - DRL relay hack, Polaris AutoTop DIY (sold)
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"
2004 996 Targa Tip
2020 BMW X3 Xdrive, 2004 F-150 "Big Red"