89 z24 chevy caviler

this may help you :
https://www.youtube.com/watch?v=X3j_r4KVZcs
good luck , i am in to Japanese tech . sorry .

Intake manifold air leak. Could be a crakced or missing hose to the brake booster. Any way air can get past the throttle plate will speed up the engine.

Sounds like you electric choke is hanging, check, alsong with your tps sensor

Pull the air cleaner off and crank the engine. If puffs of air come come out of the throttle body when cranking the engine then the timing is not set correctly. Otherwise, after cranking pull a spark plug and see if it is wet with fuel and if so this indicates an ignition problem (coil, distributor/cap/rotor or faulty ECU).

Btw, I’m available to help over the phone in case u need at https://www.6ya.com/expert/dave_fb2c45146b845cea

you may have a plugged fuel filter as you don`t say if you have changed it. also have your fuel pressure tested with a gage, it should run about 36 lbs pressure if its multi-point fuel injection or run at about 15/18 lbs pressure if its a throttle body.

You did not mention the throttle body or the idle air control valve.
The computer controls idle speed by how much air is allowed to enter the intake manifold thru the throttle body.
If the idle air control valve is faulty, or there is a vac leak, or the throttle body is dirty, the computer can not keep the idle speed at the factory setting.

If the car has high mileage, it is quite likely that the cam timing has changed due to a jumped timing chain or gear...depends on which engine it has?

it may not be a vacumn leak from a line,check the throttle shaft for movement,for example,i had a 89 1 ton 350 and my throttle shaft was moving around a lot and in order to keep it from idling high,i had to kick the throttle pedal.But also check the idle air control valve,which is the round sensor on the side of the throttle body.

sounds like your throttle positioning sensor is not set right so i would undo the two phillips heads that hold it and turn it till the idle doesnt fluctuate should be turned most of the way to the front of the truck. Also check your idle screw that throttle body could be set different.

1995 S-10 Chevy Blazer just replaced fuel pump now it is idles at 1500 RPM's what should I do.