Engine Stall problem

[deacfire]

SO here is my problem

I am having a problem with my engine stalling. Whether i am just ideling or even accelerating sometimes my car will stall. Now This is happening mostly when the AC is on as well. I can have the car ideling for 10 min fine whitout the ac on, but as soon as i turn the ac on the car will stall, and is more likely to stall while actually moving with the AC on. As well the car is ideling very low, around 500 - 700 rpm when the car is warmed up (Also car stalls mostly when the car is actualy warmed up).


The car has recently undergone a engine transplant, and this is a new problem since the engine was replaced. Not quite sure what would most likely be the culprit.

Can anyone help???

[deacfire]

Forgot to mention

it is a 1999...2.4 SE four door.... with auto tranny.... and no SES or SVS light come on when engine stalls

[rixGAphx]

'99 4-cyl, auto; 11-yrs old, about 131k miles?

What was the condition of the 'donor' engine (new/used/rebuilt, # miles, etc.) and what old parts from your car were re-used (sensors, TB, intake manifold, exhaust manifold, alt/AC/PS) and were new plugs/boots installed?

Was the transplanted engine from a '99 GA, or some other year or model of car?

How is the fuel milage in generaL: Fair for a 4-cyl,or absolutely crappy?

Offhand, it sounds like the IAC isn't working right at any rpm once warmed-up and in 'Closed-loop' computer mode.
In this mode, the PCM responds to the O2 sensor.
If that's the original O2 sensor, the first thing I would do is replace it.

[tenspeed]

Generally, when you turn the A/C on, the radiator fans come on for cooling and the RPM's increase. It could be that the system that controls those functions has failed.

[deacfire]

'99 4-cyl, auto; 11-yrs old, about 131k miles?



Yes actually :P the car description is dead one well except it had 150k miles.


The donor engine was APPARENLTLY working fine no problems. Didn't seem to have any problems when test driven. Only had 70k on it. It was a pretty straight swap of the engine. Most of the sensors on the new engine was used. Aside from the coil pack, nothing else from the old engine was used.

Haven't changed the plugs or the boots as of yet. Both are in pretty good condition from my inital inspections. Tho tomorrow i am putting all new plugs, and maybe changing the boots in a couple weeks when i can find them.

Fuel mileage is actually really good, just as good as the previous engine. I get about 275-280miles per tank of highway driving.

The replacement engine was also from a 99 Grand Am SE.

I took apart the trottle body today and cleaned it up along with the IAC valve. Still nothing so tomorrow I am putting on a new IAC.

As for the O2 Sensor, which one are u referring to? Where is to to on the engine so i can replace it?

[rixGAphx]

As for the O2 Sensor, which one are u referring to? Where is to to on the engine so i can replace it?The front O2S, on the exhaust manifold; the PCM uses its data to determine the FI.

The rear O2S, on the back of the catalytic converter, merely monitors how well the cat is doing its job.
The data from the rear O2S has no effect on engine management.