ok this is the 88 Sahara 4.2L I mentioned in a couple posts.
It stalls on throttle, if you really step on it from a stop or blip it fast it will bog, backfire out the carb sometimes, and usually stall. If you feather it REALLY lightly it will drop RPM's and act like it wants to stall. If you step down just right though it will rev normally... Once it's above about 1500 to 2000 RPMs it will rev high with no problem.
Here's what I've done so far. I've hit the whole carb liberally with carb cleaners, I've pulled vacuum lines checking for leaks, cleaned the sensor (PCV? plugged into the top front of the valve cover). Cleaned out a hose that looks just like the one I just mentioned but is plugged into the top BACK of the valve cover (close to the firewall) and has no valve... this goes to the back of the air cleaner and has a sort of filter inside the air cleaner. The filter element looks like it's supposed to trap Oil but I think it's getting soaked to the point where it's actually letting oil into the carb (judging from the air filter and the residue in there).
The only vacuum leak I found was the vacuum timing advance (I think) which goes from the bottom of the distributor over the valve cover and under the air cleaner where it Y's into some other vac lines. I pulled on this and noted a sudden rough idle. For a minute I thought I had my stall problem. The hose had a tear and pulling it made it lose vacuum. So I cut it the rest of the way off and attached the slightly shortened hose back into the Y fitting; idle smoothed back out but it still stalls.
The air cleaner housing has two problems. There's a plate in the intake which is above an inlet coming from the exhaust manifold (exhaust gas recirculation?), this plate is attached via wire to a diaphragm on the outside top of the intake, which has a functional vacuum line attached. the diaphragm is lose (no longer riveted) and doesn't seem to be doing it's job. Right behind this (closer to where the air cleaner housing meets the intake) also on top is another diaphragm (same look) this has a U shaped attachment that is no longer attached to a little plastic lever which appears broken inside (looks like there might have been a plastic plate attached to it). This is also attached to another vac line this vac line when removed doesn't suck air. If anyone wants to take a moment (or three) and fill me in on what these do and what they're called I'd appreciate it. Hard to replace something when you don't even know what it's called.
I haven't messed with a Carb since I was a teenager, and I've never messed with one that has all cludgy sensor/EPA stuff. Any thoughts on what the problem might be greatly appreciated. Even if I don't buy the Jeep I'd like to fix this problem.