I am having issues with my 4 barrel idling too high/fast. after driving it for a bit it'll get so that if I try to turn it off, it will diesel (that's what my grandaddy calls it) it basically chugs and sputters like it wants to keep going.

I tried turning the idle screw on the side down (the one with the spring around it) but the throttle plate (I think that's what it's called) doesn't go all the way back to the screw unless I physically push it back, or sometimes if I tap the accelerator real fast it will settle back.

So what is it holding it up the plate from returning all the way back? throttle cable? Please Help!

Maybe the throttle return spring is a bit weak or mounted too short.

where is that located? still trying to learn...

Your choke coil could be bad or sticking. My e4me would occasionally get stuck idling at 1500rpm and pop/diesel on shutdown because the choke coil wasn't unwinding far enough to click the carb off the fast idle (on the passenger side of the carb, near the black round disc with the single wire terminal (the choke coil) there will be a linkage with a little weight, may be stamped "E" or something similar, try pressing down on it and see if it affects idle when fully warmed up)

If the choke's fast idle cam is not holding it off the curb idle set screw (you can push it back down without fiddling with the choke on the other side) check your throttle bores for play. With the linkage disconnected, see if there's any play front to rear on the primary shaft. The throttle blades will have to be held slightly open to check this or they will keep the shaft from moving.

Play in the shaft can sometimes keep the primary throttles from closing completely. A bushing kit is required to correct it.

I forgot tto mention but I don't have a choke coil at the mooment, I had it pulled off when it was going bad. would that have any affect? what exactly does that do?

The choke coil keeps the choke blade closed when cold and slowly opens it as the motor warms up. I'd fix it and put it back.

whats the part called on the front drivers side of the engine called? has like a plunger that pushes the throttle plate, 2 torx screws that hold it to the engine and has a plug, that plugs into the top angled away from the carb a little bit. some kind of solenoid? I need to find out the name

solenoid throttle positioner?

If your throttle solenoid is holding it up, you'll have to troubleshoot as to why. One possibility is a bad TPS, which is telling the ECM that the throttle is open more than it is.

Disconnect the wire to it, see if the problem goes away. Work from there.