Hi guys. My problem is a idling problem on my suzuki sidekick 1994, 16 valve. When I accelerate, when the rpm gets to 2500, it goes up and down. I asked around, nobody can help so far.

at what RPM?,sure the 2wd has no tachometer,

Sidekick, with what engine? sure 5speed and 2wd,
but what engine.?
in 1995 they (last year this) 2 engines
the 8v and 16valve,
both, night and day different, EFI.
TBI and MPI injected, 8v is black top, 16v says 16 valves on top.
but both engines, will fail ISC controls like that if there are problems.(idle speed controls)
the surging (hunting) is one of 2 things.

1. (too lean, or air leaks)
2. or ISC lost control)
   

the ECU on the car will in fact hunt the ISC if it can not attain
800 RPM hot IDLE, that is its JOB, to do that, endlessly.
in fact 200 times a second.!
but is not working. (this control, its out of control for sure)
to find this can be easy or hard.? (luck and true causes)
depends on true cause.
I cant do both engines here, be like 10 pages.
The 8v engine races with all air leaks. and hunts. (races)
the 16v goes lean with all air leaks, (air density system is unique)
and goes slower, RPM and may hunt. no RPM stated so cant wax smarter...sorry.

so its a dirty ISC? cant close fully, ? clean it? first.
the 8v has air leaks. caused by vast reasons.
cracked hoses. leaking diaphragms, even the brake booster can leak. lots of leakage patch possible
or some one fiddled the idle air bleed screw making it fail.
try closing that valve (screw) turn it CW directly clock wise.

this page covers both systems.

http://www.fixkick.com/fresh-air/idle-air-supply.html


this ISC cleans just like the EGR that leaks.
egr leaking cause, low RPm and it too, can make the ISC go nuts.
so, but no RPM stated. so.....
eg: hunting from 1000 to 1500RPM
or hunting from 500 to 700 rpm?

i pinch all hoses first.
if RPM drops the hose is cracked or the other end is leaking air.
every 50k miles?

http://www.fixkick.com/sensors/cleaning-egr-isc/double-trouble1w.JPG

does RPM go below 800 RPM HOT engine?
yes ./no
this a is key factor.

Clean out the throttle body carefully and replace the auxilliary air idle valve. There is a resetting process for this valve so dont just fit and hope!
Check on Google or forums but i think ...when fitted you turn on ignition but dont start car , then put the accelerator pedal slowly to fully open, hold it for a min then release. start and drive car until warm and the recheck.
If the idle is high then settles it is not an air leak. It is something stuck that then releases which is only throttle flap or idle valve. It is always a goid idea to replace fuel, oil, air filters on normal service intervals.
Roger

That would be normal. I slight variation in speed is a normal thing. If it's more than 50 rpm, you've got some other problem.

Check and lube the Idle Air Control (IAC) valve,

This tiny electric motor is mount on top valve cover and close to the accelerator cable.

The function of IAC motor is to idle up the RPM when more load is added.

Example: A/C on,light on,stop light on and radio on.

A stuck IAC can be free by few soft tape on the body of the motor.

To lube the worm gear,you will need WD-40 to free up the old grease and lube white lithium grease.

Clean the electrical contacts with CRC electric part cleaner.

This electric motor is very expensive.

Please handle it with care.

Check vacuum lines/hoses and air idle screw. Also helps to know if it started all of a sudden or you bought it like this???

Buy a bottle of Techron Fuel injector cleaner. It's sold in many grocery stores and all auto parts stores. Pour the whole bottle into the gas tank when you can fill up. Drive the car and don't put more gas in until the car is almost empty. That should fix it

could be the idle are valve that is sticking.

Check throtle position sensor... one section closes a set of contacts when you take your foot off the accelerator... this is sent back to the engine control computer which adjust the timing to insure the engine stays @ ~ 800 rpm. It's easy to set with just a simple multimeter...

Once you rule out some kind of ignition problems,; spark plugs and wires, ignition timing, distrib. cap & rotor, the cause may be low fuel pressure from a failing pump or clogged filter. Listen to the pump in the gas tank. If its been getting louder lately, have the pressure tested.

)The fact that thge engine idle fluctuates when it is cold indicates that the Fast Idle THermo Valve is out of adjustment.
This valve is located ot the front of the intake manifold on the driver's side just below the accelerator cable. To adjust it, wait until the engine is cold (best to do it first thing in the morning).
Remove the two screws holding the cover on and start the engine. There is a brass needle sticking up through a plastic ring that has two slots in it. With the engine idle fluctuating, use a thin flat blade screwdriver to SLOWLY turn the ring CLOCKWISE
until the idle stabilizes. Once done. put the cover back on withg the two screws and you should be done.