Initial idle cold is 2000+ rpm start up hot is 1800 - comes down to 800 rpm.

not told hot or cold engine
the controls for idle are not the same , those 2 modes.
how high is high RPM,.
hot is 800 RPM regulated by PCM + isc idle valve.
cold is controlled by IAC,thermal air control valve.
and runs about 1200 to 2000 rpm,cold
cold in Florida is 1200 cold in ALASKA is 2000.
if the thermostat is bad, stuck open, and 150f coolant temp the RPM will be stuck high all the time
as will huge vacuum air leaks, the MAP sensor sees that and engine screams.
pully connectors is useless as doing so puts he PCM in limp home mode and idle controls are disabled in that mode. limp
there are lots more tests, to do. but my fingers are tired.
get shop to fix it?

THE ECU CONTROLS RPM ALL THE TIME,. HOT AND COLD
ON OLDER ENGINES THERE WAS AN AIR VAVLE
CALLED IAC. (pure thermal, not electric ISC)
IDLE AIR CONTROLLER THAT ADDS AIR COLD FOR HIGH RPM.
no engine told at all so there can only be an generic answer
to work on any car, learn what you have and tell it first.
or post the VIN and I tell you. what is there.
I have lots of old suzuki manuals. from long ago. but parked on my server.
800rpm hot, engine, with head lamps and blower on same time
or shifting from park to drive and RPM is 800RPM and does not drop shifted to drive, if this stays 800 the ISC valve is working
if hot RPM fails , cold has no chance, see????
engines possible

• H25/27 v7
• J20, DOHC, 2.0l gas.
• G16b, 1.6L, ,

all 4 are MAF based fuel injected not MAP vacuum based at all.
on all 4, if vacuum leaks happen engine slows from super lean mix.

if ISA or IAC leaks or stuck open yes RPM too high yes.
yes both love to stick. from 1988 to 2010 about.
today's cars are not the the same, they are TBW throttle by wire, using 1 throttle motor.
tech talk? high RPM is caused by too much metered air.!
all 4 engine run MAF metered air.

again no VIN no joy, the blind guys can not see under your hood.
sorry. (sad face)

I think should be around 750.

chech engine light is letting you know that the idle air valve has been disconnected. looks like you have a bad idle air valve.

WHAT COUNTY???????????????????????????????????
hot engine, cold or both?/// a key question
WHAT ENGINE: ( usa list , ONLY)
2.2 L F22B I4
2.2 L F22B6 I4
2.3 L F23A I4 2.3 L F23A7 I4
the fsm covers this. hose thing.... all hose can be followed,
unless its axle vents on 4wd cars. (they go no where, special)
is surging the only symtom.?
no engine stalls.?
lack of power in any gear or hills.
no misfiring?
no flooding.?
starts easy/?

ok what is surge, that it really is idle controls bad or out of comtrol
1: idle controls bad. (isc dead?)
2: or engine is running way too lean, and ISC cant keep a grip on idle.

easy huh?
and #3 misfiring so bad the idle controls fail.
are all fuses good?
is the CEL lamp glowing , then goes out running engine.
no , the scan it. or do the flash DTC codes trick.

a good tech ,first finds out if the engine holds closed loop status
hot. at idle, if not, he fixes that first.
as he/she knows that idle is the last thing to work right, in EFI.

one other way to get surge is air leaks (aka. vacuum leaks)
if the engine (unsaid option) is MAP based, it will race fast
with any vacuum leak, and it dont take much of a leak
to make the ISC idle controller go nuts.

so repost , hot/cold both questions
and actual RPM numbers. we need numbers
is the dash Tachometer missing. ????
and what engines in car.

all lean engines surge.
all ISC systems can surge if out of control , not all do this. just 1/2
if the ISC surges, it means its trying hard to gain back control.
this is called a software servo loop.
The ECU is programmed to hold rpm near say 800 RPM hot.
and is very digressive in that role.
I have a 91 car that will surge, with any vacuum leaks.
(by design) depends on which engine.

1995 Geo Metro. COLD start or HOT started or BOTH?
Does it ever idle down to 800 HOT? (engine temp)>?

Aka:
Geo Metro (later re-branded the Chevrolet Metro), Pontiac Firefly, and Suzuki Swift
which engine, what country??? I will post for USA only !!!!
Auto or stick tranny???
the USA 1995 was the last car to use TBI injection (throttle body)
the LSI option, then had a 4 cylinder. in 1.3Liters.
and works totally differ. than any 1.0L
answsering for 1.0L

Have you inserted the Diagnostic jumper wire and looked at the
FLASH codes yet?
choke? on 95? what country is this, ours are not carbs. in 1995.
so post country. ours are all EFI in USA.
3 cylinder? 1 liter? or which engine/?
on any USA Metro, 1L , when first started, it has 2 valves. to control IDLE, (cold , is iAC) hot is ISC, The cold start valve opens farther the colder it is (how cold was it). but usually is limited to about 2000 rpm
max.
this engine, TBI, uses a MAP to control fuel mixtures, and
any air leaks (aka; vacuum leaks) what so ever, will cause too fast idle.
so on MAP cars, you get to find out what is leaking AIR.
1995 has the new better , idle control speed motor, (ISC)
this can be stuck open.
that new TPS, did you do the calibration correctly?
it must set right. or idle will never be controlled.
finding the cause, takes hard work, and hands on testing
A/C fast idle broken
A/T transmission fast idle, device, broken.
Air leaks (add huge list of possibles and cracked hoses here)
Throttle stuck
ISC or IAC bad.
very hands on to find this, done many.
TPS on indexed corrrectly or not calibrated.

check all vacuum lines very closely for a vacuum leak. might be a small hairline crack that is hard to see.

double posted
post RPM in both modes,
it must be the same
the ISC idle controls system controls idle at all times.
post RPM. 800 is normal. the exact valve is in the FSM
and posted under the hood in USA.
no country stated in 4000s posts so.... well, gee....
here, open the hood, look up, see EPA vacuum map
that is also the the engine size and type , and most state the normal
hot RPM clearly there, and is in the FSM.

here is the acid test. hot.
in park hot, rpm 800 if not the ISC fuction is dead
"idle speed controls"
good? yes.
then select drive. if RPM drops ISC is malfing.
now back to park. (all this is in the FSM to read)
now 800 hot. you turn on all heavy electrical loads
the rpm does not drop. Head lights + heater fan, and defrost.
all these test he ISC, if it fails its bad.
what does bad mean, that means its out of control
and you do further testing to find the reasons.

vast reasons.
Ill name 3:
intake air leaks. aka vacuum leaks.
ISC valve dirty , clean it.
throttle cables , misadjusted.
cold start air valve stuck open hot.

check all your vacuum hoses and the throttle body itself for a vacuum leaks if the hoses replace as nessasary if to check for throttle body get can of carb cleaner and spray around base of throttle body and sides not in it if idle raises you have a vacuum leak goto a good parts store and ask for a rebuild kit don't goto auto zone or advance they don't carry them

sound very much like a vacuum leak.... also maybe your timing is off? possibly advanced? try retarding it with the distributor if thats the case...