The CEL is on. I have a 1997 K1500 Silverado. The code is P1345 "Manufacturer Control Ignition System or Misfire". Odd thing is it seens to run fine. Any thought as to what I should look into for the problem? FYI I tried clearing the code to see if i would come back and it does just a few seconds after start up.
As I understand it, P1xxx codes are often manufacturer specific, so, to get a good code definition you need a source that knows GM codes, not just generic codes.
That said, it has been a while since I've seen it, but it seems like P1345 was the code that points to the "timing" being off (or some other fault inside the distributor).
Have you recently done any work on the distributor or work that required removing the distributor? If so, this usually indicates that you didn't get the distributor back on in exactly the right position. Get a high end scanner (one that can read the cam retard parameter) and adjust the distributor until cam retard is 0 +/- 2 degrees.
If there hasn't been any recent work that would throw the timing off, then you can check the timing, but it might be indicating some failure or pending in the distributor. If a tune up is due, it might be worth the time to get the tune up out of the way.
I have not touched this engine. I will Google the code. Is there a site for that?
I haven't found a good website with manufacturer specific codes. Best sources for information on code diagnosis I have found is a good repair manual (I find that many libraries have these manuals, some have subscriptions to online manuals for their patrons). You might also put the code number into this site's search engine, as I'm almost certain we have discussed it here before.