1991 geo storm stalling at idle

GEO what, must we guess the car.
tracker
metor
Prizm
storm.
and then with that we guess 10 engines? really?
all we know brett is its a GEO XXXXX
1993 (other post, discloses its a 1993 and NOTHING else.)
why?????????????????????

what year did it last run ok. 1994?
ever heard of a cell phone camera and post a photo of car
and one of engine.
yahthink?
THIS GEO?

need to check your idle sensor. its going out

additive? for what reason, for stalling? or just for fun added.
you didnt say.?????
if it was for bad running, did you read the container, ?
and add the correct amount on a full tank of fuel, if not , then you may have added too much, some additives are very bad,
next time use Techron fuel additive, (if you feel compelled)
if the car runs bad no fresh fuel, and all 4 sparks are fouled.
no additive is best. fouled sparks are from other reasons.
50 reasons. and not one is cured by magic in a bottle.
I run Chevron fuel in my car, so adding more benzene is of no help
ever.
you said plugs, that to me means, (????)_all 4 are fouled.
4 plugs changed, where they spec type spark plugs, J plugs.
and were the gapped to Geo Storm spec.
if new plugs foul? that means (all 4?) means its running rich.
top reason for rich are:
1: thermostat missing or stuck open (engine never reaches normal temp)
2: Sensors reading wrong,
The Check engine lamp, what does it do.?
Is CEL light glowing key on,. then out after starting, (no? then pull the DTC codes and read the problem)
too high fuel pressure, ask your mech to measure that. or DIY.
ECU stuck in limphome mode. check DTC codes for reason.
Dead , bad or weak sensors.
leaking injectors
Ask any ASE mechanic, to just diagnose the problem.
then you have your answer. but many shops never seen a GEO ever
and have no documentation. on these.
how ever alldata dot com has it.

get a multi-metor and check the egnition system. Distributor could be worn(could have saved my self lots $$$).

Sounds like your idle air control, or IAC valve. Take it off and clean it out with some brake cleaner. Carbon deposits and gunk can build up and prevent the IAC valve from operating properly, by causing it to stick. If cleaning it doesn't work, you may have to just replace it. It happened to me on my Sentra, tripping my check engine light, sputtering hard, idled crazy, no power, etc. But once I cleaned it off, it ran so smooth. You'll need to get a replacement gasket, though, or make your own out of gasket paper.

Remove the battery cables and clean the cable clamps and the battery posts.

Put cables back on and see if that cures the problem.

Let us know.

Haynes manual shows this for that problem, but please take it with a grain of salt and dash of peper:

1. Idle speed incorrect
2. Fuel filter clogged or water and impurities in fuel system
3. Distributor components damp or damaged
4. Faulty emissions system component (talk about vague :)
5. Faulty or incorrectly gapped spark plugs
6. Faulyt spark plug wires
7. Vacuum leak in intake manifold or vacuum hoses
8. Valve clearances incorrectly set

That last one is possible IF the new timing chain/belt was installed a tooth off.

All info is from a Geo Metro/Sprint Manual, but it may help.

When you say "fixed", do you mean that you put the new belt on it?
If so, you probably missed a tooth in the belt placement. This usually happens when you wrap the wrong way during the procedure and the marks don't end up lining up.
Also check for other things like pinched wires or something disconnected that didn't get put back in the right spot. (vacuum lines?)

RPM's up and down check EGR valve and sensor. EGR valve and sensor control idle. That's why your getting the surging on rpm's and this could be giving out the other codes. If mass flow was bad car will not start and the same for the map sensor. O2 sensor measures gas and air for right mixer. TPS controls 0-60 speed as in throttle respons.

Try this
Here are the most common causes of surges, stalls at stops, low erratic idle speed, rough idle and engine hesitation, 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.