Hi there …
2000 Chevy S10 pickup
Had the check engine light come on, and when I checked on the code
it gave a 4th cylinder misfire. Autozone instructed me to simply replace my spark plug with a new oem plug.
I replaced the spark plug as instructed.
After about an hour of driving, the check engine light goes off and I think, great! Problem solved.
However, another hour of driving and the check engine light is back on again, without going away.
I headed back to autozone to get a readout, just to find that it’s the same code.
So I put another spark plug in.
Same result - check engine light goes off after an hour, only to come back on again permanently after another hour.
Now, normally I would think, this must be the spark plug line that needs replacement,
however I am sure there must be some clue in the fact that the check engine light turned off for an hour.
By the way, not sure if relevant, but I also found a lot of build up around the spark plug before I initially changed it.
In fact, there was so much that I had to scrape around the plug with an awl, and blow out the crud with a compressor,
just to get my socket into place without there being crud in the way.
Anyone have any clue what that check engine off/on clue might be?
Thanks so much for your time.