So I have got the codes:
P0303- Cyl 3 misfire
P0335-Crankshaft position sensor A
Blazer has trouble turning on sometimes. Runs decent then it will get sluggish rpms will fluctuate up and down sometimes not all the time. Truck will turn off while idling and driving sometimes. So I decided to inspect the sensor today. I didn’t get a before picture only after I cleaned it. The 3 wires were stripped and touching each other and full of black grime I cleaned them up and plan to wrap in elec. tape. Could this have very well been cause of P0335?

After cleaning

 

My guess is Yes - Use Plasti coat - Permatex liquid tape - or such type of coating to coat the bare wires then follow with tape if wanted - it will seal and protect better

 

Well to no avail I taped up wires and it ran a whole let better. I even made it home without it dying! But still have Codes-
P0335(crankshaft position sensor)
P0303(misfire cyl 3)
I did happen to change plugs, wires, fuel filter upon purchase (3 weeks ago)
I currently have some injector cleaner running in gas tank. Going to do a little more digging and see about some diagnostic

hope I don’t have to replace sensor and do relearn not sure if my scan tool is capable of relearn I doubt it is

 

You can do a lot of research in this section:

Diagnostic Trouble Codes (DTCs)

 

Thank you I’m going to buy a bi directional scanner after work and a shim and pull off sensor to see if it has been rubbing

 

I purchased a scanner device from Amazon and it connect to my phone. I am able to remove codes and I think you need to do that. I would not think that you would need shims but where is all the oil coming from. It sure ate your wires up. My front cover was leaking oil and I washed it off with spray cleaner and finished it up with alcohol and a toothbrush; then added permatex silicone copper to it and left until next day. Did stop leaking.
After clearing codes think your misfire on 3 will be gone than.

 

I’ve cleared code 3-4 times and not sure about the oil yet

 

I pulled the sensor out and sure enough it had been rubbing and all of the black plastic stayed inside of hole except a small section that stayed connected to sensor I fished all the plastic out with some needle nose and installed new on with 1 shim (0.5 thickness) I bought a Bosch OBD1150 bidirectional scanner to perform the relearn but it either isn’t capable or I couldn’t find it.... hopefully it was the latter.. although blazer turned on first try seems to be running smoother and driving 10x better I cleared all DTC before installing so on my morning drive to work we will see how she acts and if CEL/SES comes on.
(I attached photo of my scanner also maybe someone is more familiar with it)








This is why you need spacer so it won’t get worn down...

All of the black plastic cover/coating worn down/off

 

Well not sure if anyone is following but I had contacted Bosch to make sure I wasn’t overlooking it and they informed me the scanner is indeed not bi directional (even though O’Reillys website clearly states it “is”). I called 2 Chevy dealers in the area just for a laugh and 1 quoted $225 the other $130. I called one local shop and guy said he could do it for $40 but we have 2 different lunch breaks and he closes at 430 and I get out at 5 (LOL). I did speak to one of my friends (Thursday) that has a Snap-on triton he will be busy till tomorrow (Saturday). Guess I should’ve just waited before buying the Bosch scanner but I figured for the price why not. Patience is a virtue or something like that. Will update y’all when I do happen to get it relearned.

 

I sure dropped the ball on that one. Thank you for sharing; I will remember that. I replaced the distributor in my car and had to do a relearn from all that I read. Cost $150 and threw a code on the way home. Turned out to be a bad plug.