97 2.4 what would cause the engine to surge it goes up and down when you stop you can run it hard it does good untill you let off the fuel or go to stop

is this AFRICA KB240 , 2.4L petrol.?????????
we have no KB here in USA not a one. no parts, no books on it. (heck no WIKI on KB. ouch)
so it starts and drives ok/
but idle surges (up/down RPM) means PCM can not control IDLE RPM at all, and has many causes.
you can drive it fast and even up hills or at WOT.?

but only stopping at say a stop sign the engine surges.
well lets work that 1 problem if is just 1.
EGR struck open, is common. (if has one)
IAC stuck the idle air controls valve is stuck and needs cleaning, of gunk off it
thermostat not bad, 180F (82c) is good but 150 is bad. hot normal engine.
VVT failing . if has VVT. (cam timing variable)
VVT engine most times have no EGR valve.
spark wires bad, seen on new cars with no COPS.
seen with COIL packs and 4 HV logs and 4 HV wires
and HV wires bad, or just one.
as I said no books here on KB at all. zero.
as in service manuals.

Really bad idea and very UNSAFE. If you have a wreck and the engine stops, the fuel pump could keep running causing car to explode and kill you! Fix it correctly.

if flooding, (and this causes MISFIRING)
there is an injector leaking
no year stated,
not scanned ? , why not scan it.? got p03xx codes.?

you replaced expensive parts before spark plugs. really?
do a full tune up, ?

There is no "One" answer for this problem. You will need to run tests to confirm. What have you checked, tested, repaired, or replaced so far? Is the Engine Light on? If so, I need to know what the codes are. Please have them read. From you description, it sounds like your vehicle has a vacuum leak. The ECU is having a hard time controlling the idle. Check for vacuum leaks at hoses, the plenum, and brake booster. Check the EGR and Idle Air control valve. Check fuel-line pressure (check it with the engine off and compare it to the engine running). It is hard to test O2 sensors unless you know how to but you can remove them and do the "Shake Test". All you do is remove the O2 sensor and shake it next to your ear. If you hear a rattle noise, it is junk. It is possible that one or more fuel injectors are dirty, clogged, or worn (causing this issue). The more information you can provide me the better I can help you narrow this down, good luck.

(which engine. ?????)_
as always check all fuses. and scan the ECU for DTCs. first.
there is no need to fix OBD2 cars like 1980 cars (hard rows to hoe)
it can be 2 problems this......
lets fix the easy one first. idle. (and hope for moving issues to fix for free) it idle car is parked, so is 100% safe tests. (not moving)

so it surges at idle.
questions.?
1: hot or cold or both.?
2: low extreme RPM and high at idle.
400 to 800 RPM? surge.
1000 to 2000. what? numbers tell the tale.

first off, idle is the last thing to work right on any engine.

there are many ways to find what is wrong.
fix idle surge way.
i make sure that the engine holds closed LOOP status.
hot idle, if not , i fix that first.
keep in mind if not in closes loop and lean
all lean engine surge and guess what the ISC will add to the surge
because idle is way too slow, so the ECU open the ISC wider
and wider and its still too slow, so the ECU resets the ISC
this cause a worst hunt (surge)
the ECU adjust spark time and the ISC to get 800 rpm. (spec. look up yours)
so say , i see closed loop failed, OBD2 scan page 1
i look at the O2 sensor an its stuck lean.
if stuck lean and it really is (o2 bad?) then its lean and it will surge
.
examples.
1: i find 02 sensor bad, (only effects idle and light steady cruise)
2: i find fuel pressure at 15PSI , hopeless low .
3: i find all injectors clogged. and lean.
4: with MAF EFI, ( i find maf reading too low, (dirty) causing lean.
5: if MAP car, i find the MAP stuck hard high vacuum causing lean.
not knowing what engine you have or the idle hot surge range,
i can not go farther.

the driving bog tells me,
1: scan the ecu ,get DTCs; do that first.
2: clean MAF if car has one, ask how..
3: check fuel pressure.


my guess is engine is lean. and starving for fuel all the time.
cept WOT.

MAF cars starve for fuel if there are any vacuum leaks.
MAP cars do opposite, they race fast with 100% full power.
MAF is air density EFI
MAP is speed density EFI.
apples and oranges diffr. so what engine.

Sounds like fuel problem to me?? Have you changed the fuel filter ?

CLOGGED FUEL FILTER OR WEAK FUEL PUMP CAUSE CAR TO HAVE LACK OF POWER AND SURGE.CHANGE FUEL FILTER,CLEAN FUEL INJECTORS WITH CAN SEAFOAM BY ADDING TO 3/4 TO FULL TANK OF GAS.CHECK FUEL PRESSURE SHOULD BE 41 - 47 PSI FOR 2.0L OR 3.1L ENGINES AND 9 - 13 PSI 2.2L TBI INJECTION SYSTEM.IF FUEL PRESSURE GOOD CHECK TRANSMISSION FLUID LEVEL.FAULTY TORQUE CONVERTER WILL CAUSE LACK OF POWER AND ENGINE SURGE.A STOPPED UP MUFFLER OR CATALYTIC CONVERTER WILL TAKE SLOW CAR DOWN MAKE IT SPEED UP SLOW DOWN SPEED UP SLOW DOWN.

run engine codes, had same issue once before it was bad computer good luck

You will need to check the Mass airflow sensor and the Idle position sensor.

Get a good alternator not a cheap one.