I need some tips. I am having problems with what I think is coming from my carb. When I drive at a constant speed of at least 45  mph (in the same gear, whether it is 2 or third) but for at least 20 minutes my 1986 chevy k20 350 starts to stall out, like there is no gas going to the carb. Eventually I can't even drive my rig. My distributer cap is some what screwed up and I am going to replace it tommorrow. I think it might be from that. Would vacuum leaks do this? I think i have come to the conclusion that it begins to happen when my engine starts to get hot (it is not over heating) For example it doesnt stall out when i am driving around town and i have to stop a lot at lights and stop signs, so the engine never really gets to hot, but when i am on the highway it gets really bad.

Any thoughts

Thanks

Paul

VT

hi there!  you were correct to check your distributor, that could cause stalling, but i would think that would be all the time, not just when the engine is hot.  check your plug wires too, and maybe for the correct gap in the plugs.  Also check for vacuum leaks, like you said.  finally, the choke could cause such a symptom if if is improperly adjusted or engaging randomly or something.  driving slowly, having the choke closed may not make a difference, but it certainly would at higher engine speeds.   maybe you could try out a different carb to see if the stalling continues, borrow one from a friend or something?  Hope this helps a little.  

Thanks a lot, i am about to go and change the distrubiter and plugs. The choke seems to be acting funny two. When I have the rig runnning, and i close and opent he choke it doesnt make a difference in the RPMS, SHoudlnt it?

Thanks

Paul

there may not be mauch change in the RPMs but if you step on the gas with the choke plate closed, the engine will probably be starved for air, y'know?  That may explain why it acts fine at low RPMs around town but stalls at higher RPMs.  Still you did say that it only has that symptom after 20 minutes or so at highway speed, right?  I'm not sure what would make it delay like that.  It's strange that it would run fine for a while, and then act up....  

After it stall's what do you have to do to start it again?  If you have to crank it for a long time then you probably aren't maintaining pressure in your fuel line.  I know a lot of Chev's have trouble with their fuel pumps that cause the same sort of effects you complained about.  Easy fix: get a clear fuel filter to install by the carb then you can tell if you have fuel when the truck stalls. 

If it isn't the fuel pump it could be the fuel filter/pick up is getting plugged up when you have a high demand for fuel(more vacuum pulling gas out of the tank) the dirt in the tank will plug up the fuel pick up.  then when the engine dies the vacuum is released and the dirt can settle back to the bottom permitting the truck to start and run again.

Good luck

thanks for the input. Maybe my tank is old and rust could have formed which might get into the fuel line, the fuel filter looks very clear though and it is only a few months old. I am going to chekc the modual in the distributer to see if ti is burnt out. i will get it test at a NAPA. I changed the distributer cap and it ran a little better but it is still having th eporblem. It only happens after the truck is heated up.

I will check these things

Thanks