Misfiring and popping with p0300 code
Thread Starter
On The Tree
Joined: Feb 2013
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From: Shawnee, KS
Joined: May 2004
Posts: 1,593
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From: Halfway back on the Highway to Hell...again!
Any small thing will cause a misfire on these. I've seen the tiniest nick on a lobe or roller that makes it misfire. Or can be something more severe. i.e. bad lifter, bent pushrod, misaligned rocker, broken spring, bent vlavle, injector, coil coil wire, etc etc etc. I've seen just about every possible scenario...and there's alot of them. Even broken rings, ring lands or pistons.
Thread Starter
On The Tree
Joined: Feb 2013
Posts: 138
Likes: 24
From: Shawnee, KS
Any small thing will cause a misfire on these. I've seen the tiniest nick on a lobe or roller that makes it misfire. Or can be something more severe. i.e. bad lifter, bent pushrod, misaligned rocker, broken spring, bent vlavle, injector, coil coil wire, etc etc etc. I've seen just about every possible scenario...and there's alot of them. Even broken rings, ring lands or pistons.
Thread Starter
On The Tree
Joined: Feb 2013
Posts: 138
Likes: 24
From: Shawnee, KS
Originally Posted by Dark_Side
I will try that. I guess I'll shoot for something around .035-.040. I had them at .050 for years
Thread Starter
On The Tree
Joined: Feb 2013
Posts: 138
Likes: 24
From: Shawnee, KS
I actually did check them out and poured some 10-30 oil over the rocker arms and Springs to help pre lube them before first startup. Then after I test drove it and noticed the problems, I did pull the valve cover again to double check because I came across a few threads of similar problems and they found broken Springs or bent valves. As far as I can tell I didn't notice anything wrong
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Verdad Gallardo Thread Starter
On The Tree
Joined: Feb 2013
Posts: 138
Likes: 24
From: Shawnee, KS
I put in 8 new tr5's at .035 . I found a plug that wouldn't click at all and push back off (fresh dielectric grease) on #8 cylinder. So I went and got new wires from autozone. After brand new plugs and wires, HPtuners says cylinders 5 and 7 still misfiring.
Last edited by Dark_Side; Jul 30, 2022 at 12:33 PM.
Thread Starter
On The Tree
Joined: Feb 2013
Posts: 138
Likes: 24
From: Shawnee, KS
I figured it out! 5 and 7 coil trigger wires were switched at the male main plug. Even though I double checked it a few weeks ago I still over looked it some how. I knew it had to be something small I was overlooking.
I want to thank everybody for all the help and suggestions!
I want to thank everybody for all the help and suggestions!
Joined: May 2004
Posts: 1,593
Likes: 267
From: Halfway back on the Highway to Hell...again!
I didn't have them stripped down to the wires. I only wrapped on top of the factory wrap, so the form of the wire harness stayed in the exact same shape. I did depin the bulk connector to paint the white plug but I took pictures of the wires and triple checked I put them back in the exact same spot.
But hey, You figured it out and that's all that counts. Cheers, Man.
We've all been there and still make simple mistakes daily...well most of us. Others are conceived as the best car builders in the world.
Thread Starter
On The Tree
Joined: Feb 2013
Posts: 138
Likes: 24
From: Shawnee, KS
I really only came across it when I was reconfirming the continuity of the trigger wires between PCM and coil and noticed 7 wasn't registering
