Help!! Random misfire now constant knock
 

I have a 2001 Chevy Blazer trailblazer edition. I've had bad problems with it not starting in the rain. So I changed the standards wires, cap, rotor and even coil. Still same problem. So i changed all the above PLUS distributor iself. Truck starts great now even in the most heavy of downpours. Well recently started having random misfires (Flashing check engine light) They seem brief then go right away. It seems to happen more at a certain rpm, never in overdrive. Well, yesterday going up a fairly steep grade it done this and something happened, the tach started jumping and now i have a constant knock. The noise sounds half crank speed so i took off both valve covers and everything looks great. I saw no excessive lash, no broken push rods, or collapsed lifters. I'm at a loss.. The motor still is running but the noise makes me not want to run it.. :/ It is my familys only vehicle and i cant afford any down time. Also have smelled rich fuel smell during misfire moments.. I don't want to jump to conclusions with saying it needs a rebuild and such. Its got 140,000 miles. Anybody please help! Thank you

I'm just reading some related posts waiting for help myself. To me, random misfire is a P0300 code with a steady not flashing CEL/SES. Do you mean occaisional or intermittent steady SES or a constantly flashing SES? It would be good to have your codes read and posted here, although the constant knock sounds like you need to take it to a good repair shop ASAP.

Update!!
 

After more investigating the intake is soaked with fuel and i believe the knocking and even squeaking i'm hearing is bearings that all the excess fuel washed down. It sounds horrible, so its out of my hands now and i'll be getting the grim details tomorrow after work.. I've read so many problems related to this i'm almost certain this was a spider poppet failure and or regulator failure causing all the excess fuel. I believe i was thinking the opposite with the misfire's vs over-fueling. Sad day for me. This is a beautiful truck, and hard to find trailblazer edition. Being said even though i live in Maine this is absolutely rust free (amazing!!) so I'm not going to give up on her!!!