Car cuts out went to a guy he reved the car so bad now doesn't idle properly,cuts out more now than before. now has a hissing noise sounds like air. replaced plate under the carb.

MAF sensor or idle jet dirty or clogged, a can of carburater cleaner through the intake after air filter (while reving) may clean it otherwise a service may be needed.

If it is a carby model it could be loose or blown gaskets,spray around the area with WD 40 to find the leak.

Possible vacuum leak. Check all hoses under hood for cracks/disconnections/leaks. Will be heard by a hiss type noise. You may have to scan computer to monitor sensor operating parameters with a scan tool to isolate this problem

First if the "service engine" light is on I would have a local retailer or garage see what the codes are. For possible TPS, IAC, or mass air flow problems. TPS being "throttle position sensor" IAC being "idle air control" If a light is not currently present, listen under the hood for a hissing noise or signs of a vaccum leak.

You provided no info on the vehicle motor,so
I would assume you may have an Air Idle Solenoid
next to the throttle or on the intake manifold,that you
can remove & try cleaning or replace.

Could be high temp sensor not functioning properly

Clean or replace IAC valve (idle air control valve).

think you have damaged the unit ,you will need to replace it .

Hi there;
It sounds a lot like you have a vacuum leak, I'm assuming your car if fuel injected. If there is too much air getting into the engine from a broken vacuum line of possibly a stuck Idle air control motor the computer has to keep adding fuel to make sure the fuel to air mixture is right. the end result of this is the engine RPM's keep going up untill it reaches the propper mixture.
If you are under the hood with the engine running you may hear a "HISSING" noise. It may be loud, it may be subtle, so you might need to listen fairly close.
The job of the idle air contol motor is to bring the idle of the engine down to the proper Idle rpm in a controlled manner without the engine stalling from a sudden loss of fuel from letting your foot off the pedal, after a while these start to get sticky or weak & don't work propperly so this may be the cause as well.
If you don't hear any hissing & can't find a vacuum leak, you'll need to suspect the Idle air control motor.

Good Luck I hope this helps
Farrout!

yes that is the expansion valve! there is a hissing sound from the restriction in it for a pressure drop thats what makes the a/c cold the hissing is normal