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Re: Intermittent Misfire
Posted: Wed Jun 15, 2022 7:44 pm
by JayG
Changed both the coil and plug.
Still get P305 code at low RPM every now and then
Re: Intermittent Misfire
Posted: Thu Jun 16, 2022 4:22 am
by 32wildbilly
JayG wrote: ↑Wed Jun 15, 2022 7:44 pm
Changed both the coil and plug.
Still get P305 code at low RPM every now and then
What did the old plug look like when removed. Just dirty or oil fouled or carbon bridged?
Re: Intermittent Misfire
Posted: Thu Jun 16, 2022 6:26 am
by JayG
32wildbilly wrote: ↑Thu Jun 16, 2022 4:22 am
JayG wrote: ↑Wed Jun 15, 2022 7:44 pm
Changed both the coil and plug.
Still get P305 code at low RPM every now and then
What did the old plug look like when removed. Just dirty or oil fouled or carbon bridged?
Just a bit dirty, a little cooked. Ill post a pic in a bit
Someone suggested it might be an injector issue. I'll run a bottle of techron or seafoam through
Re: Intermittent Misfire
Posted: Thu Jun 16, 2022 9:37 am
by 02TX996Cab
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.
Re: Intermittent Misfire
Posted: Thu Jun 16, 2022 11:48 am
by FRUNKenstein
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 (361.75 KiB) Viewed 2132 times
Re: Intermittent Misfire
Posted: Thu Jun 16, 2022 3:46 pm
by JayG
02TX996Cab 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.
I dumped a bottle of Redline SL-1 fuel system cleaner in the tank. Need to drive it a bit and see
Where in TX are you?
Re: Intermittent Misfire
Posted: Fri Jun 17, 2022 6:16 am
by theprf
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
Posted: Fri Jun 17, 2022 9:09 am
by 5chn3ll
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...
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
Re: Intermittent Misfire
Posted: Sat Jun 18, 2022 5:25 am
by JayG
JayG wrote: ↑Thu Jun 16, 2022 6:26 am
32wildbilly 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?
Just a bit dirty, a little cooked. Ill post a pic in a bit
Someone suggested it might be an injector issue. I'll run a bottle of techron or seafoam through
Re: Intermittent Misfire
Posted: Fri Jun 24, 2022 5:47 am
by JayG
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.....