My 2001 pt idles fast in drive and in park idle goes up and down like surging

HOW HIGH IS TOO HIGH RPM? (NO TACHOMETER?)
NO ENGINE TOLD OF MANY SO ANSWERS NOW GO GENERIC.
ALL ENGINES CARS, FAST IDLE LOCK IS BASED ON ECT SENSOR COOLANT TEMPS, AND COLDER IT IS THE FASTER IT GOES.
EVEN BY EPA LAW USA.
cold is 1500 to 2500 most cars. pcm logic hard facts. and tables.
fluctuates is super bad and dangerous A.K.A SURGE.
there is no pat answer to this, so many engines.
but here are some.

• IAC BAD. (IDLEAIR CONTROLEER VALVE) THERMAL
• ISC STUCK (IDLE SPEED CONTORLLER ELECTRIC.
• THERMOSTAT BAD, OR MISSING.
• ECT READS WRONG/ Most times see 1 line up.
• VACUUM LEAKS FROM VAST THINGS. (YES VAST)
• PCM IN LIMPHOME MODE NOT SCANNED AND IDLE CONTROLS 100% OFF LINE. AND SURGING.
• GROSS MISFIRING.
• GROSS LEAN BURN AND SURGE.
• other sensors failing hard and you not scanning PCM miss the boat.

.

well gee, there are 50 reasons.
did you scan the PCM yet, if not ,why not?
when the idle surges, that means.
NO RPM ranges stated, if super low rpm check EGR.

1: engine lean and ISC dead, or cant handle the huge engine power drop..The PCM can even make this worse!, buy hunting the ISC to find spec, idle and failing... to...
2: or any of 50 other things causing huge engine power drop and PCM can't maintain idle controls.
super lean burn.(bogging)
super rich burn, misfire for 50 reasons.

i cant hear your engine,nor feel it, or see it shake from gross misfiring.
no can i drive it and see/feel power loss,
can I?
asking net bunny's this (blind as bats)
is "OVER THE TOP" no?
so here , ill toss the dice for you
and guess gross misfiring.
ever get a tuneup this decade, if not bingo , no?

and the others...

http://jeepdied.com/Misfire101.html

link even has the 50 cause list, to show the futility of guessing!
we do 1 to 10 tests. and find it.
for sure.

as you can see EFI systems are complex.
gue$$ is not only expensive but can net you 2 problems easy.

Idle air control motor. Clean it or replace it.

idle air control valve is dirty or fast idle thermo valve is not working correct idle air control is behind the air Pentium fast thermo is below throttle body

usually cleaning the idle speed contrlol valve from carbon buildup, fixes idle surge and stalling. try soaking vave in throttle body cleaner or inyector cleaner.

hot engine
cold
or both
in drive, or park, is this a stick shift car, i dont know.

this is called surging idle. and all EFI love to do that at a drop of hat.
ALL
the hot idle is 800 rpm
bad idle surgine is caused by.
1: EGR leaking.
2: lean combustion for any of many reasons, is EFI holding closed loop status at hot idle, (no , fix that first.
3: ISC is out of control (ISC electric is the ECUs idle controller)
the ISC goes out of control easy.
EG:
a: egr LEAKS.
B. AIR LEAKS.anywhere in the induction path (AIR path)
illegal leaks, MAF engines go lean, MAP engines just race fast.

4: ISC is stuck (clean it)

with all cars. we:
1: check all fuses
2: check the CEL is it glowing running,? yes, then scan it now.
3: check with scan tool for closed loop hot. if fail fix that first.

and lots more..... but i stop here.

code p 1193 refers to inlet air temp sensor problem --circuit high
a faulty ambient air temperature sensor or barometric pressure sensor will cause this effect as the idle control in the ECM is not getting correct temperature readings to set idle speed

Have you install a timing belt recently? If you get it off a tooth it will idle high and surge

Here are some of the causes of surges, stalls at stops, slow idle speed, erratic idle speed, rough idle and engine hesitation (and other problems), it is in most cases the idle speed control air-bypass valve and or throttle valve and upper intake, these area's get full of gunk and combustion residue over the miles and cause idle issues (stalls, low idle) like yours, Get a can of intake cleaner from any local parts store, not carb spray, intake cleaner, it is made by a company called CRC, remove the air intake hose to the engine, hold the idle high so the engine won't stall, then spray the can of cleaner into the intake while keeping the engine running, use at least 1/2 the can, shut down the engine and disconnect the battery for 5 minutes, then restart and complete a number of mixed driving cycles, town, freeway, stop and go etc., after a few days the problem will go away as the system will relearn to the clean intake

I have an 87 Accord with fuel injection that always had a fast idle, and a surging problem when warming up. Both problems went away when I replaced the fast idle valve, which is bolted to the rear of the intake manifold just downstream of the throttle body.