P0300 Random Misfire figured out.

**swtnlow1** · 09-17-2016

After weeks of changing parts and scratching my head, I found the cause of my random misfire. I went to change the harmonic balancer and crank sensor, and after removing the balancer, I found that the screws holding the reluctor ring on were loose. I applied Loctite to the screws and retightened them, and like magic, the misfire was gone. Took about 30 minutes. This is a free check, and beats spending money chasing a ghost. I have seen a lot of people struggling with this problem, and I sure hope this helps someone. Wish I had found it sooner.

**J57ltr** · 09-17-2016

That's interesting for sure I'm surprised it didn't take out the crank sensor. Must not have been very loose?

**Turbocharged400sbc** · 09-17-2016

it was probably replaced with a dorman balancer, ive had to swap the tone wheels over, though now I think they come with them

**swtnlow1** · 09-18-2016

Not sure of the history, but the balancer that I bought to replace it had 4 screws in it, the one on the car only had two. After several weeks of driving, I still have not had any misfire codes come back up.

**swtnlow1** · 09-18-2016

The screws were just loose enough for the rings to rotate, not really wobble, guess I got lucky on that one.

**swtnlow1** · 11-19-2016

After 2 months of driving, still no new misfire codes, just wanted to give an update.

**Silver2kgtp** · 11-21-2016

I assume the reluctor ring is on the balancer?

**J57ltr** · 11-21-2016

Excellent info.

Yeah it's on the back of the balancer.

**Silver2kgtp** · 11-21-2016

Thx. I have a power Bond SFI balancer. Gonna pull it off and check.

**Slick2500** · 11-21-2016

Sal still chasing down that misfire are ya?

**Silver2kgtp** · 11-21-2016

Lol. Yes I am. I've changed and upgraded just about everything.
I might even put back stock balancer just to rule out SFI one.
Next is starting from complete scratch with a new tune. If not that then I'll have to pull engine out