So im new to rangers/B4000's the issue im having is a idle of 1200 and sometimes 1800-2000rpm. When i come off the highway i takes forever to go down and stops at 1200-1800rpm's. i scanned and pulled up these codes:
P0153
P0102
P0113

now what i have done is as follows, seafomed the engine and intake, cleaned throttle body. engine oil change. Where shud i go from here?

 

lil update i just got back in i took the mass airflow sensor out n cleaned it along with a new air filter. i also did the thing with the iac sensor where i unplugged it and the vehicles idle fell drastically but did not die.

 

Welcome to the forum

Was the 4.0l OHV engine warmed up for the IAC Valve test, it needs to be

The fact the idle dropped when you unplugged the IAC Valve means it was being opened by the computer, and then closed/moved when power was removed, which is a good sign that it is working

IAC Valve and computer are very accurate at setting idle RPMs, +/- 3rpms is spec
The IAC valve gets 12volts on its red wire with key on, the other wire goes to the computer, it uses a Pulsed Ground to vary the voltage, this is called PWM(pulse width modulation) and is used on several systems in vehicles since the late 1980s

If engine is warm then idle should drop to 500rpms, barely running, or stall, if not then there is an air leak somewhere
Do the Vents in the cab work OK, they are vacuum operated
Do the power brakes feel OK, they are also vacuum operated

Do you have a manual or automatic transmission?

In 1997 Warm idle on a manual should be about 700-750
Automatic 750-800

Codes
P0102 Mass or Volume Air Flow Circuit Low Input<<< yes clean it
P0113 Intake Air Temperature Circuit High Input<<<this is on the upper intake passenger side, 2 wires, unplug it and check connector
P0153 02 Sensor Circuit Slow Response (Bank 2 Sensor 1)<<< drivers side O2 sensor on the exhaust manifold pipe, if over 100k miles change BOTH of the upstream O2s

 

manual

 

vent seem to work fine switches between defrost and other modes and brakes are fine also. i checked the lil hose under the throttle body and its fine looks new actually

 

Air and gasoline mix is 14.7 to 1 ratio and this is a weight ratio not volume, so.........
14.7 POUNDS of air to 1 POUND of gasoline
or
14.7 grams of air to 1 gram of gasoline

At sea level air is heavier than at say 5,000ft elevation, i.e. LA or Denver
Warmer air is lighter than colder air, i.e. "hot air rises"

Gasoline's weight doesn't change all that much with temp or elevation
Air's weight changes ALOT with temp and elevation

The P0102 code can also mean the TPS(throttle position sensor) is acting up, 3 wire sensor on throttle body, unplug it and plug it back in, this cleans the connection

The computer uses MAF sensor and TPS to compare air flow data

Computer "knows" its running a 4 LITER engine, so it "knows" exactly how much air will be coming it at any RPM, its just math
MAF sensor tells computer the WEIGHT of the incoming air(is it sea level of 5,000ft), TPS tells computer the LOAD on the engine

The IAT(intake air temp) sensor, P0113, modifies the MAF sensor data because Air temp matters, so this could set MAF code as well

 

kk ill give it a shot n get back to u

 

ALRIGHT so last night i unplugged the IAC and disconnected the battery over night for around 10hrs. Started it up tonight and let it get up to temp by running for 10mins or so. It was idling at around 600 rpm wich is where i want it! So i took it for a drive and im still having the hanging issue when shifting into neutral when coming to a slow or stop. The idle hangs around 1300-1500 then SLOWLY goes down like VERY slowly sometimes not at all and just hangs at 18000rpms. Should i clean the IAC now as that is the only thing i haven't cleaned?

 

Check throttle cables, gas pedal and cruise, to make sure they are not holding throttle open, also throttle spring, you need a good strong spring to close throttle plate on a running engine
And just generally see if throttle operation is smooth when its closing, even the TPS can cause an issue hold throttle plate open a bit

Emissions
RPMs should hang for maybe 15seconds, when shifting, that is required to pass emissions, idle RPMs pollutes big time, but it should drop down to about 1,200rpms after 15 seconds or so with clutch pedal down or in Neutral and coasting
Idle will stay high(1,200) until speedometer drops under 5MPH, for same reason
This was added in 1995 and up computers to pass emissions

Now-a-days engines must shut off when you stop, i.e. auto-stop/start, to pass "idle" emissions

 

could u direct me to a new spring for the tb? it does have 180,000kms on it so id rather replace it. i seem to cant find one and my local napa or parts store dont know also.

 

Not sure if it is sold separately, may need to get the whole throttle body

But you can add a temporary spring to the linkage to see if that's the problem

 

whelp now it seems worst...started today. after sitting outside for a day went to start it today and after it gets warm idle goes down to 7-800rpm but idle is VERY rough almost like a heartbeat up n down up n down up n down...im thinking the mass airflow is pooched...as it seems to have gotten worst since i cleaned it. Gonna save up some cash and do a huge tunr up to see if that helps. intake gaskets both upper n lower, spark plugs/wires, new mass airflow sensor. fuel filter, new iac gasket after i clean it. throttle body gasket after i clean it, valve cover gaskets....gonna be a month or so till i get to that. If that dont fix it i dont know where to do then