I have an 89 4.3TBI S10 Blazer Sport.
Got a new problem 2 months ago, it would start and run very well for 30 min or so, then feels like losing power a little, idle drops and becomes rough, engine light comes on (but never when it's on idle, only when driving up a hill) for few seconds (checked it, got code 13), normal temp.
A week ago, after I drove it for 30 min or so, turned it off, when I tried restarting it, it clicked but didn't crank, like the battery was weak, but started normally on second try. That happened twice in 2 days, so I tested the battery and found it was in great condition, and I'm sure it's not the starter, because I changed it like a year ago, so I tried retarding the distributor a bit (turned it CW). Didn't feel any changes in idle or anything else, but the starting problem didn't happen again.
2 days later, I sprayed some CRC Clean-R-Carb in the TBI and in the small hole on top over the IAC side with the engine running and revving it.
Turned it off, restarted it 15 min later, drove it for 30 min, parked it. When I tried to restart it 3 hours later, it cranked but wouldn't start. After trying many times, I left it there, and went back the next morning, it started on 1st try. And since then, when I drive it, if I turn it off, it will restart if within 15 min or so. If I wait more, it will not restart before 8 hours or so! I tried advancing the distributor (as it was before) and retarding it (different positions), but still had the same problem.
What could the problem be? Knowing that I have new AC Delco distributor cap and cables, and spark plugs under 6000 miles.

 

Check the fuel pressure sounds like its starving for fuel

 

I don't think so, because I tried pouring some fuel down the TBI and that didn't make it start. And why would it be starving for fuel if warm?!

 

oh you got a tbi i was thinking of the vortec mine had the same exact problem and it turned out to be the spider

did you rebuild the tbi yet ?

 

From what you have described, sounds like condesation build up in the distributor. I know it's been discussed on here in length and what the fix is. Just can't think of it off the top of my head.

 

Condensation in summer?! I don't think so, but maybe I should open the cap and take a look, and maybe spray it on the inside. That would do no harm

 

Yes, condensation in the summer...

in south LA. Didn't even notice your location...lol.

 

Didn't get to check it out today, will do it tomorrow, and I live in Beirut suburbs in Lebanon - Middle East

 

Believe me, I know where Beirut is. I spent 6 months off the coast back in '83-'84.

 

Update: Yesterday I started my Blazer and took it for a 15 minutes drive, came back, parked it, left it sitting, came back in 10 minutes and it restarted at 1st try. Came back in an hour and it wouldn't restart, so I took out the IAC (which is less than a year old) and found it clean, but cleaned it even more, put it back in place after making sure it was extended to specs, took off the cap and cleaned all the terminals on the inside and out, and cleaned the rotor contacts. Still wouldn't restart.
This morning it starts at 1st try, then an hour later it wouldn't restart, so I unplugged the cable off the central post on the cap (the one from the ignition coil), put a screw driver on the tip, put it close to the chassis (ground), and asked my wife to try starting it, and there was no spark at all!
What could the reason be?! Why would I not have power out of the ignition coil only when I leave it sitting for over 15 minutes after it's warm?!?!!