84 ford ranger with a rebuilt engine. Sat for about 10 years. Towed it home thinking it would make a fun project. Engine was seized, resolved it with a combination of pb blast and some mystery oil. Old carb was leaking from the butterfly bushings so I ordered a new one. Now I’m having some seriously frustrating issues. When I put it in gear or turn the wheel it drops about 800 rpm. The wheel is gradual, depending on how fast I turn it or let it go but the in gear is a steady drop, I can run the truck if I raise the park idle to 2k and loosened the mixture screws to about three and a half turns out. Now the first thought I had was a vacuum leak that’s only noticeable under a load. I started off with some break clean, sprayed it around the engine with it running. Found a few bad lines and replaced them. Still had the rpm issue, so I moved on to the break assist, found a leak there so I unplugged, and capped it from the main vac. Still had the issue so I moved on to the egr valve. It was letting some air pass when I blew through it so I made a block off plate & gasket. Still an issue. Getting a little frustrated I capped all the vacuum lines from the main vac and the carb aside from the pcv valve. Still a leak so I tried changing to a mechanical issue rather than focusing on a vacuum leak. I replaced all plugs and plug wires. Adjusted the timing by ear, and gave about a 10 degree variance to be sure, but no noticeable change other than the rough idle.
Now I’m thinking maybe it’s a timing advance issue or my pcv fitting. Shook that and it rattled, but for the cost it probably wouldn’t be a bad thing to replace. Now, the distributer has a mechanical advance, I plan on pulling the cap to check the play and if the rotor springs back, but I’ve noticed a few of the wires have been chewed. Aside from that I’m just grasping at straws. Have any of you had similar issues or maybe heard anything? I’m open to any suggestions
sorry for the long paragraph