1999 Mazda Protege Engine stall at idle after battery chang

You may have a vacuum leak, get a can of spray gumout, spray the vac lines and maniflod area, when the idle changes, youve found the leak! You want the engine running and spray on the outside but do direct the stream onto the hoses, if it is a vacuum leak, the engine idle will change speed, then you have detected a leak, repair the vacuum leak and see how it runs! If that doesnt do it, you may need a new idle air control valve, it's bolted to the throttlebody

Thanks. I will try.

OK Let me know...the other thing is the computer takes a short time to relearn the way to operate with the sensors. How many miles have you driven since the battery change?

It continue to happen for 2 days about 30+ miles right after I changed the battery.

So Day before yesterday after work, I switched back to the old battery. Its has much less rough idle, almost as good as before. Only 2 times it get rough and like to stall but never did. It happened when I completely stopped at the red light, the engine at about 700rpm idle very good for 5 seconds (still in D)... but then it start to go rough...

BTW, what you mean by "spray gumout" is the

Carburetor & Choke Cleaner

right? Thanks

Yes spray gumout, or spray throttle body cleaner.
You might check the ground cable from the battery to the engine and from the PCM to the body ground point.

Is it normal that one time spray will rev the engine and other time don't?

There are multi place that I spray will change the rev the engine:
1. engine and between the intake
2. around the throttle body

However, it won't do multi times. i.e. If I wait some time and try to spray at the same area again and again.. it won't rev...
So may be the rev "just" happen when I spray over there?
It does not repeat tell me I may not on the right track.

The P0171 code came back 2 days ago ( I started the engine at the morning, the engine light stay on from turn key to engine start...it should had turn off, but the code was there). BTW, I tried the MAF spray clean before.

When you did the spray test with gumout, you left the air intake intact? Spray was on the outside of the TBI? You may need a new gasket for the throttle boby. Or the gasket between the IAC and throttle body, recheck with the spray and let me know...P0171 is a lean code, usually cased by either too much air or not enough gas. Fuel pressure OK?
https://www.2carpros.com/car_repair_video/test_fuel_injection_pressure.htm
Go here and checkout our video.

Thank you very much for the reply.

I left it till Sat to start to fix it.

I get the throttle body out.. sort of because I can't found a way to disconnect the acceleration cable...

I clean the throttle body and replace the gasket to the manifold from dealership (It broke apart when I take out the throttle body).

Now the car start with 3000rpm and eventually slow down to 1750rpm (setting ask for 700 +/- 50rpm)

The car run but it won't like to slow down because of the high idle

I try the adjust idle speed but turning the screw has no effect (with or without the shorting of the TEN and GND) on idle speed.

Unplug the Idle speed unit plug (IAC) will have NO change in the idle speed (idle as car was "Parked")

So is the IAC gone bad? or there is something I forget? or pulling the acceleration cable (when I try to move around the throttle body) cost a problem...

I think I figure out what is the problem.
The throttle do not close tight.

If I put some force to make it close tighter, the idle speed go lower.

What to do?