Car stalls when it warms up

That could be sometihing to do with the throttle position sensor, MAF and idle controls. Once the stalling is resolved, the problem could be rectified as well.

Questions -
1. Can you expand on what to do with the idle controls?
2. Where is the Throttle position sensor located?

Note - I already cleaned the throttle body, IAC and MAF sensor.

TPS is the black component with the white cap under the IAC.
Idle controls means the IAC and throttle body itself. These are linked to the engine computer and vacuum leaks would affec them as well.

So since I cleaned the throttle body, IAC and MAF sensor, what else should I look at?

What's causing the car to choke and stall when I give it gas?

Since you have performance related problems, other than the idle control, the fuel pressure and TPS would be the next thing to check.

Testings of the TPS requires a scan tool.

Will a multimeter do?

Found this:

The main and only item in the tool list is what is called an ohm volt meter. Once you have identified the TPS sensor, turn on the ignition, do not start the car, make sure the volt meter is on twelve volts DC. Locate the connector that goes from the ECM (engine control module) to the TPS. Once you find this disconnect it completely from the throttle position sensor. There are three prongs; the center prong is usually the negative connector.

Once this is done, take the volt meter and connect the negative side (usually the black wire) to the ground terminal on the battery. When this is done take the positive lead, (usually the red wire) and attach it to one of the other prongs. The volt meter should read five volts, if you are on the reference wire for the TPS. If it reads anything below five volts then you are on the signal wire and need to go to the other prong in the connector. If it reads nothing on the volt meter then you are on the negative connector. Once you locate the reference wire, and it reads five volts then you know that you are getting proper reference voltage to the TPS. Therefore you have just eliminated a faulty power feed to ECM.

Questions:

1. Is this the correct procedure?

2. Are they referring to the car battery?

No, a multimeter would not. The procedures are correct for testing the power feed from the PCM, which is required but you need to test the TPS which requires a scan tool.

Yes, the battery means car batttery or any ground on engine would do.

When I press on the accelerator, the acts like I'm revving the engine and then threatens to stall.

If I let up on the gas, the engine settles back down.

Any thoughts?

Symptoms are consistent with a TPS fault.

It is easy to change out the TPS?

I kind of doubt you have a TPS problem. I think the engine computer relies more on the TPS when the engine is cold, but your problem is after the engine warms up. But here's something easy that is worth a try: Unplug the electrical connector to the TPS and try revving the engine in the way that makes it threaten to stall. If it is no better, plug the connector in again and forget I said anything. If it IS better, try driving it that way, up hills where it usually stalls. If it is like my car, your automatic transmission will shift funny while the TPS is disconnected -- mine would not shift until about 4000 RPM. But if disconnected cures the stalling problem, that's a good sign the TPS is involved.

P.S. You said the fuel pressure was checked and was OK. Was the volume also checked -- that is, could the fuel pump maintain pressure when delivering lots of fuel, as opposed to idling or before even starting the engine?

Has ignition timing been checked? (I'm not sure if that is even adjustable with your car, but bad timing could cause problems at higher engine speeds and up hills.)

The puzzle to me is, why did the problem go away for a week after the first shop worked on the car? Did it REALLY go away, or was that just wishful thinking on your part?

No it really was working; I was able to drive it out of state (60 highway miles) with no problems. It ran perfectly for 1 week before the problem reappeared.

Well, I am not a mechanic so I hesitate to suggest more than what I already did. It sounds like the first garage you mentioned is the only one that did any good for the car. Maybe you can go back to them and say, "You fixed the car but the problem came back in a week". Remind them nicely that you spent a lot of money and don't have any left, and see if they offer to at least check it again to see why their fix didn't work.

You're NOT a mechanic??? Then what are you doing on this forum giving car repair advice?

Is there anyone there who is, who can help?

Please pass me to a certified mechanic.

I tried what you suggested -

"Unplug the electrical connector to the TPS and try revving
the engine in the way that makes it threaten to stall.

If it is no better, plug the connector in again and forget
I said anything. If it IS better, try driving it that way, up hills"

Result:

1. The engine idle was much higher - stuck in the 2000 range

2. My brakes stopped working - they got spongy and not stopping.

When the TPS is disconnected, the PCM is not going to recognise the amount of throttle opening and this would result in it reverting to preset values. Such test do not show you anything.

What you need to do is to plug in a scan tool to test or recalbrate it.

Have you rechecked for trouble codes? Tampering with the TPS would throw codes and it is best to clear the codes and go for test drives first to let the computer relearn and set codes if any are present.

I would still put my money on a faulty TSP.

Thanks for taking over. I've seen your profile; are you well versed with Chevy cars?

I do not own a scan tool nor can I take it for a spin because it stalls.

Questions:

1. If I had a scan tool, can it be used with the recalibration?

2. What is the procedure for doing a recalibration?

3. Would it be easier to just change the TPS?

Welcome back

I am an arm chair mechanic now and no, I am not well versed with your vehicles. I only work from the information I have and the years of experience with auto repairs.

Whatever information provided is what we work with and if you give us the wrong information, we would get nowhere.

1. Yes
2. The procedures I had shown previously shows how to recalibrate the TPS.
3. Yes, changing the TPS would be an easier option but without any testings, you are only guessing it is the cause and you might be throwing good money on a risk.

Can you please send me the scan tool procedure for the TPS recalibration?

Sorry, I thought I had sent you the procedures which were for the IAC.

For your model, the TPS cannot be adjusted but you can check its calibration. If it is out of specs, you need to replace it.

V6 THROTTLE POSITION SENSOR

1) Ensure engine is at normal operating temperature. Install 3 jumper wires between TPS and TPS wiring harness connector.

2) Turn ignition on with engine off. Connect a DVOM to Dark Blue and Black wire terminals. With throttle at closed position, adjust TPS to obtain specified voltage.

3) Tighten screws and recheck readings. Turn ignition off. Remove jumper wires and reconnect harness connector to TPS.

TPS ADJUSTMENT VOLTAGE

At idle RPM or closed throttle. .50-4.8 V

As you said, KHLow, "When the TPS is disconnected, the PCM is not going to recognise the amount of throttle opening and this would result in it reverting to preset values."

Exactly my point. If the car will rev and go up hills when it is getting no signal from the TPS, then we will have isolated the problem to the TPS, or to the wiring between the TPS and the computer. Trouble with braking probably just means the engine is idling much higher so it is harder to stop the car.

Rmonet2012, my apologies, I was not trying to deceive you about my expertise as a mechanic. I do have some experience, but I am not about to hang out my shingle and open a repair shop. Anyone can respond to questions here, and from reading other threads (not this one) I can assure you there are many less qualified people providing "authoritative" answers.

Well it would have been nice to have a heads up. Because the brakes were not working, I nearly slammed into a tree across the road.
The car died and had to be pushed back to the driveway.

I changed the TPS and the idle seems to be
stable, but I have another problem now.

The brake petal sinks down to the floor and the brake fluid is low
again after I replenished it. It looks like a I have a leak somewhere.

Q - How do I check (trace)and located the leaky brake line?

Q - Is it easy to fix or do I need to get the car to a shop?

The brake lines goes from all wheels and should not be difficult to detect if the leak is bad.

Work depends on what is leaking. Check all wheel and brake caliper first. Look out for signs of wetness.

Found a leak by the left (driver's side) rear tire.; not sure if it's the hose or brake line. Are there any videos that show how to repair it?

The car starts fine and warms up with no problem - idle level are within normal range (600-800), temp is good and oil pressure is level.

The car sounds great for about 5-10 minutes; then the idle gets rough and eventually stalls. I have to wait for the car to cool down before I can start and keep the engine on.

Someone mention that the ECU might be the cause to the stalling. The 91 3.1 Corsica has a documented record with ECU and fuel injector problems.

What do you think?

If you do not have any trouble codes, it is possible for the ECU to be the cause.

Do you mean impossible or possible?

Can it still be possible for it to be the problem without any codes?

Possible and yes, no codes showing.

What is the procedure (step-by-step)for replacing the ECU?

Removal

Ensure ignition is in OFF position. Disconnect negative battery cable. Remove electrical connectors from ECM. Remove ECM from vehicle. Remove MEM-CAL or PROM and CALPAC (if equipped) from ECM.

What are the steps after I connect the new ECU and start the car again?

Let it run for a while and go for a test drive to allow the PCM relearn .

Someone mention the stalling problem may be caused by a bad tcc.

What do you think?

Check for trouble codes.

TCC fault would normally cause engine to stall when gears are engaged.

Would a TCC fault cause the car to stall if I give it gas while in park?

It should not if you are giving gas but would stall once the gs is released. If you want to do this test, you need to monitor the engine rpm. If rpm goes up to more than 2k, the torque converter is not stuck.

Is this the TCC plug connector?