I'm diagnosing a pending code for P0300 (random misfire).
I'm starting with the distributor cap and rotor to check for wear and tear. The cap and rotor was replaced about 18 months ago, so I don't expect it to be at the end of its life just yet. I did have an issue before where the terminal pin in a previous rotor broke causing a fatal breakdown, so that's why I'm suspecting the cap and rotor first dealing with this random misfire.

I see a major burn mark in the center of the rotor, and several burn marks inside the cap. For an 18 month old cap and rotor, I'm just asking if this looks like major wear.
Also I have a photo of the distributor with the rotor off. Does that part look liek there's major wear around the camshaft sensor? This is a factory original distributor and camshaft sensor. Never been removed.

 

Notice how the terminals on the cap have the corrosion from the spark on the leading edge and spark seems to be tracking sometimes between terminals. So it seems rotor isn't quite where it should be when the spark comes through. This position is measured by "Cam Sensor Retard" and can be checked with a capable scan tool. Should be zero +/- 2 degrees. Since distributor is locked in place, common cause is worn distributor gear and/or slack in the timing gears. But typically this would make the rotor position late, not early. Cam sensor is magnetic so no wear there.

Check distributor gear (is there play back and forth when you wiggle the rotor back and forth) and adjust Cam Sensor Retard if necessary. Once that is correct, replace the cap and rotor with Delco parts only. Hint: If removing/replacing the gear on the distributor shaft, don't put it back on 180 degrees off - this makes it 1/2 tooth off (with the odd number of distributor teeth). Use the dots if present or mark the gear to shaft relationship - or put an old style hold down on the distributor so it can be turned a bit.

Good luck and best wishes for a successful repair.

 

@LesMyer There is some wiggle. I'm guessing the distributor gear is worn.

(Wow, 20mb limit on my 24mb gif after my 2mb MP4 isn't an accepted attachment. Posting video here isn't easy!)
https://cdn.discordapp.com/attachmen..._174017253.mp4

What capable scan tool do you recommend for cam sensor retard? I've been trying to do everything with Blue Driver, but it's just lacking features.

 

As I understand it - Blue driver is supposed to read cam sensor retard. They might call it something different with CMP in the name.

I just put videos on youtube and link to them. Then they appear right in the thread
I think this is the same distributor everyone had been getting from Skip White Performance in the past. Use delco cap/rotor.

 

It's not "Timing Advance for Cylinder #1", is it? I can't find "cam" anything in the live data list on my Blue Driver app.

A totally new distrubtor, huh? I'm guessing mine does need replacing then.

 

if you end up replacing the gear on original, its about the same price.

Ill see if I can find out what Blue driver calls it.

 

I submitted a support ticket. They seem to doubt that BD supports CMP Retard, but they're looking into it.