I just got a minicab with a carbureted 3g83 engine. Idles OK but under a load pops out the intake. Going to try plugs and wires first wondering if anybody else has had this problem and if anybody has suggestions on what kind of plugs to run. I have already cleaned out the carb, checked timing,compression, and vacuum.
My first suspicion on such an issue would be a major issue timing, but if you have already checked that then perhaps have a look at the valves. It could be that the exhaust valve isn't opening well forcing the gas to just pop out since it can't pass through. That's my opinion.
Thanks for the comments guys but I finally figured it out. My truck has the three cylinder and somebody put a four cylinder distributor in it and apparently a three cylinder cap fits it.
Ohh, that's an interesting one wondering how the guy was able to get it work before you had that issue. Anyway, it's a good thing that you finally fixed it.