I have a idle problem with my passport when I crank it, it idles at 2000 RPM and drops down to 1300 RPM and RPM stays high between changing gears(5 speed).I have changed Idle cylinoide tps and PCM(brain). When vehicle is reset it runs perfict for about 4 days then returns back to high idle.

FORGOT TO SCAN THE PCM I SEE.
check all fuses.?
not told
fails hot and cold engine or both
car must be in transmission DRIVE selected? right?
and foot off gas pedal (accelerator)_ rpm goes to 2000 or up to 6000 rpm . and or
so driving foot off the pedal and RPM goes too high
or in drive, I step on the throttle (gas) and RPM shoots way high
and Never leaves 1st gear. that is transmission failures.
in DRIVE.
if rpm also goes that high right foot doing nothing and in park
that is engine idle control's failing.
we can not see you drive or how. so answers can be a tad hard.
in what gear? PRNDL (choices)
right foot doing what?
and what SPEED is too slow 20 or 85mph? or?
does tranny fail to upshift?

It's called IAC - idle air control valve > Did the RPM'S stay at 2000 or drop back down ? The PCM engine computer controls IAC valve according to engine load . Put it in gear , turn on electrical loads , headlamps , A/C etc... an the RPM raise's up so engine will not stall . More then likely the throttle plate needs to be cleaned , they get gummed up an stick at higher idle . Quick Tip Throttle Cleaning EricTheCarGuy If the IAC valve were gummed up the idle would be low or erratic . On some engines a vacuum leak will cause high idle . Videos on youtube checking for vacuum leaks .

It is a little high but if the ambient temperature is very low it would be ok providing you understand that there will be a bit less economy. You can fine tune the choke to drop another notch on the accelerator cam so that it would idle at say 1500rpm and the gear engagement would be less harsh

I would look at the cold start injector first and work from there.

almost sounds like the cruise control is engaging

that is because the reason the vehicle is idling so high is because there is a vaccum leak somewhere and it is sucking in cold air

yes that is high try down to 5% which will change your shift pattern.

your idle is compensating for poss air leak like vac or idle air motor,does it settle down as it warms up .if so then a poss coolant sensor is thinking that it is 50 below.hence a very rich mixture and a idle which will hunt.idle air motor maybe plugged with carbon.also disconect the battery for couple of mins.start and hold idle high about 2000 rpm for 5 mins if all above does not work.

Check for a sticking throttle cable. A vacuum leak can also cause a high idle.

what is thye correct idle rpm in park 1999 amigo