idle adjustment screw bottoms out early

[TerminalVelocity]

1995 240sx ka24de w/manual trans, 175k


I'm trying to adjust idle speed on my s14 following the standard fsm procedure (engine warm/tps unplugged/using screw on IACV). However, the idle adjustment screw bottoms out with my idle still at 780rpm (with tps unplugged). I need to get down to 700rpm for the factory specified 750rpm idle with the tps plugged in. Any ideas why the idle would be high at the lowest adjustment? The car idles smoothly so I'm ruling out vacuum leaks (Seem reasonable?).

Thanks.

[moso]

its possible someone tried to adjust the idle at the throttle plate, check the throttle stop screw and adjust if necessary.

[TerminalVelocity]

its possible someone tried to adjust the idle at the throttle plate, check the throttle stop screw and adjust if necessary.

Ah good idea. I'll check that.
Thanks

[pacman88]

Things like I/H/E, cams, etc can make the engine breath easier and not allow it to get where its specified. I found that out with my engine. Once the header came off, the engine idled down where specified. May be coincidence, but that's what happened to me.

[TerminalVelocity]

It looks like I've found a fix. As part of the tuneup process I was going through, I replaced the spark plugs and plug wires. Took the car out for a drive and noticed it tried to die every time I clutched in. I pulled the car back into the garage and backed out the idle adjustment screw and noticed the car idled better. Took the car back out and got her warm. Then I brought her back and fine tuned the idle. Now she idles perfect at 750rpm.
I'm not sure why, but it looks like new plugs and wires fixed it.