How do i stop the hard shaking at idle 1989 240sx searched, but no help

[AN89HATCH]

I have an 89 s13, and at idle i can not get it to stop shaking, it shakes as if its an old school muscle car haha, and it will not keep a steady idle, it idles at 700, then drops to 600 then up to 750, and will keep doing the same thing over and over agin, as the idle moves thats when the car starts to shake. Any suggestions as to what the problem is? thanks

[nrcooled]

Check all vacuum hoses and fittings. Clean out your throttle body along with making sure that your AIV valve is adjusted propperly.

If all of those check out then make sure that all your grounds are good

[Thieu]

I've had the same problem for a while. I replaced the IIC, air regulator, all vacuum lines, took off the EGR, took off the AIV, and it still does it. Everything ignition related is recent, as well as a Z32 fuel filter. Next step is a new TPS, FPR, and Fuel pump.