My son's 99 Blazer, a few weeks ago wouldn't start. Has been running great, easy start, no missing, I went over that after noon to help trouble shoot....motor would just spin over, seem to not be firing at all, but smelled like it was defently getting gas! Pulled a plug an was getting fire! I finally got back in an spun it over about 30 seconds an it finally started hitting , by petting the peddle kept it running till it burned the flooded cylinders clean! An ran an started fine for 2 weeks! After a lite rain...did it again last week!!! After setting for 3 day's, it started again! It cranked all weekend...till this morn....it's been rainning again, no start! Ok.....1st thought is to replace the distributer cap! Moisture!Any other sugestions if that doesn't fix? We tried a new coil the 1st go around an it didn't work. Thanks for any suggestions! Larry

 

if it is cpi motor i wold deff check the spider injection line one of mine was leaking fuel or try regulator

 

Personally, I would start with replacing the spark plugs.
The plugs these days don't seem to clean up after being saturated with fuel.
Replacing the dist. cap is probably a good idea.

 

I'll concur with the replacing the distributor cap. The fact that this happens when it is damp outside points straight to an ignition problem. You may have spark, but it may not be strong enough to fire the fuel/air mixture in the cylinders.

I would start with a full tune up consisting of plugs, wires, cap and rotor. Also, you can remove the ICM (ignition control module) and coil and have them tested at a local Advanced Auto or Autozone.

 

I'm having this exact same problem. Did you get it fixed? Mine was doing this, I called my mechanic, he said probably plugs/wires. Have an appt. for wednesday, then today it starts fine this morning, then this afternoon it wont, this time engine wont turn over at all! no click from the starter either. I can hear the fuel pump come on though. What the hell.

 

what ever the cost is, for replacing spark plugs,,, it is worth it. I did mine myself,,,never again. spend the extra and get autolite platinuim plugs, no more worries mate

 

GM had a TSB about moisture build up in the distributor because of clogged screens at the base of the distributor housing...they recomended punching out the screens and drying it out...but you should also check to make sure that all your wires and connectors are still moisture proof.

Also check all plug wires to make sure that they are properly seated, I have read on some threads/forums that plug wires can work their way loose on the cap because of excess air pressure build from installing the cap end boot onto the distributor by just pushing real hard...to make sure that this does not happen you can use a small pocket flat blade screw driver while pushing the boot on the cap it will make sure that the air has a route of escape...