Intermittent Misfire

[5chn3ll]

That was his alt/burner account.

I believe you can email johnny.irish@imatwat.com

I thought it was johnny.irish@imaidiot.com

[Black-Out]

UPDATE

Started having the P305 code again

I scanned with my durametric and now see P1371 Valve lift control check sum and P1364 valve lift control Cyl 5

any ideas on fixing?

If I drive it am I in danger of an engine failure?

Hello, I’m an old member. It’s been a minute since I’ve been here due to some health issues, but I’m back. I literally just dealt with a p0301 issue, and I think I can shed some light on the process. Basically everyone starts with plugs and a coil pack on the offending cylinder, and this almost never fixes the issue, largely because it’s not the issue at all.

What typically happens most of the time is you get a residual build up of garbage in and around the lifter on high lift mode. The lifter of the offending cylinder gets stuck in high lift and when you come back down to idle speed you end up with a misfire because the rest of the lifters have returned to low lift cam profile while the cylinder stuck in high lift mode is causing the cylinder to lean out.

Usually it causes a misfire until the engine reaches 3500 or so rpm. The actual fix is to replace the lifters, but if you wanna try to fix the issue without getting into the engine use the snake oil method. Pour half a can of Seafoam into the engine oil and let it idle for about 30 minutes to an hour, let it cool for a day and then restart it and see if the misfire gets less apparent or disappears completely. If it does then take the car for a drive periodically giving it the beans in the drive to redline. Doing this engages and disengages the high lift portion of the lifter enough that it can actually allow the Seafoam to clean the garbage off the lifter that’s causing it to stick. After about 30-45 minutes of driving if that’s the problem you’ll notice right away that the engine runs smoother and the misfire and spitting at idle through the tail pipes will disappear completely. Change the oil and carry on.

When I went through this I had a sketchy valve lift solenoid and that made me not trust the others so I replaced all 4, tossed new plugs in it because it had been a while, and tossed a new coil pack on the offending cylinder. I also at the same time put an AOS on it because mine was old, put new manifold gaskets in it, put a fresh oil filler neck on it, fresh cross over vapor hose for the AOS to the right side cylinder head, and tossed on fresh vacuum lines for all the Vario Ram intake operation and other control solenoids for the air injection. Still had the misfire.

I started thinking about the high lift mode and how it functioned and decided to try tossing a 1/2 can of Seafoam detergent in the engine to see if it would help clean the engine and it worked. It wasn’t instant. Took about a day after running it an hour then letting it cool down then running it again for 30- minutes and then taking it for a drive. It’s cheaper than putting all new lifters in it straight away, it’s easy to try and takes no effort. If it works for as it did for me, you’ve won. If not you haven’t lost any money other than the cost of the Seafoam.

Hope this helps.


William-