Weird idle then stalls

[Blaiser17]

Ok well I have a 91 camaro RS. I recently have done a tune up (plugs, wires, distributor, rotor). If my car is run at idle at lights and stop signs too long the idle will begin to sputter, and then the RPM's will slowly drop until the car stalls. When I pull up to a stop and I hear it start to sputter, if I throw the car into park for the entire stop, it will idle fine. I do not understand why it would do this. Sometimes this fails, but most of the time it works. I do also think that I might have vapor lock. Air is blown out of the gas cap when I loosen it sometimes. I do not know what could be the cause of all this. Possibly a clogged catalytic converter, bad idle air control, pcv valve, vacuum leak, tps sensor, or fuel pump. I recently have had the fuel lines replaced along with the fuel filter, and the injectors have been cleaned. I was hoping that someone might be able to point me in the right direction before I just go replacing everything. Your responses are more than appreciated. Thank you in advance.

[wrightz28]

This all started after the 'tuen-up' ? Retrace your steps, make sure your plug wires are in the corrrect order, and fully seated.

Vapor lock does not occur with sealed port injection.

[Blaiser17]

No, this was occurring before the tune-up. If it's not vapor lock, then why is air blown from the gas cap? It make a big "whoosh" noise. I have a feeling I have to replace the fuel pump. Once my new fuel pump/injection tester comes in maybe I'll know.

[wrightz28]

Originally Posted by Blaiser17

, then why is air blown from the gas cap? It make a big "whoosh" noise. .

Because the system is sealed with the pressure ahving nowhere to go. You have sealed tank systems and vented systems, which have a vented gas cap in which this phenomina does not occur.

Vapro lock is a condition in which air/fuel vapor is trapped in the lines and starves the motor of fuel.

Definately get your hands on a fuel pressure gauge, a must have tool.

Is it safe to assume that the check engine light is not on?

[Blaiser17]

Yea, I have a gauge coming in, I ordered it it should be in by tomorrow. It is a must have though, you're very right. The check engine light is not on tho, you're right. It only comes on when I leave the car run at idle in park for more than 10 minutes. Other than that it never comes on.

Thanks so much for filling me in about the sealed system, I did not realize that at all. I was worrying about something that wasn't a problem at all haha. I'll definitely let you know what my fuel pressure is when I get the tool. How hard is it to drop the tank and get the fuel pump? Any tips if I have to do that?

[Blaiser17]

Well I have finally had the chance of checking my fuel pressure and it is 42 psi. It's steady there all the time, it even holds for about 20 minutes after the car is off to let me know there are no leaky injectors. The idle has not been as bad lately but I think it has something to do with the temperature. I still have the problem of the check engine light coming on about 10 minutes after the car is idling warm. I think it may have something to do with the catalytic converter.

[wrightz28]

If it's were a catalytic problem, it would make itself apparent under load when exhuast flow is heavier.

Atleast now we can rule out fuel, hooking up a gauge, is a whole lot easier than assuming it's a pump an dspending a long day on it for nothing huh?

Can you sitll not get a trouble code out if it?

[Blaiser17]

Yea you are definitely right about just testing it instead of going wild and crazy and buying stuff I don't need

I know I can smell rotten eggs sometimes, but the converter never glows at night or seems to get crappy under load. The only evidence would be that smell, but this I still do not believe is the root of the problem. I was searching on here and found that the ICM could be bad. Does this sound about right?

I have an OBD II, but I'll get my hands on an OBD I to see what code is thrown when the check engine light comes on. With my luck though that'll take days cause it's only once in a while that it'll come on. It's like that car has a mind of it's own. But the code should still be stored from the previous times right?

[wrightz28]

Originally Posted by Blaiser17

I have an OBD II, but I'll get my hands on an OBD I to see what code is thrown when the check engine light comes on.

Umm, you odn't need to buy a "scanner" for OBDI, can you say paperclip or jumper wire?

Seriously, that's all you need there.

I got to thinking on your previous post and I'm leaning a little further more on a bum CTS (coolant temp sensor), it would explain why it 'seems temp related' and the excess fuel being dumped (which make sure it hasn't contaminated your oil with fuel. )

[Blaiser17]

Ok well I did the paper clip thing, I got a code 45. Which means oxygen sensor rich. Is this the root of the problem or just something else?

[wrightz28]

Originally Posted by wrightz28

.

I got to thinking on your previous post and I'm leaning a little further more on a bum CTS (coolant temp sensor), it would explain why it 'seems temp related' and the excess fuel being dumped )

Maybe a cause and effect. .

[Blaiser17]

Ok well I replaced the coolant sensor about 4 days ago. Since then the car has puttered at idle a lot, but it did not actually stall out, so I figured maybe the sensor was the key. Well I took the car for a longer drive today it puttered every time it came to a stop. When I came home it stalled out as I parked in the driveway. So it appears I still have the same problem. No codes were thrown at all. Although the new sensor did make the rich fuel ratio code go away! So I guess thats one small thing to be excited about. Any more ideas on how I might go about this? I'm pretty stumped. If it has fuel, has spark, has power...whats left? Some time next week I am going to hollow out the cat, I'm sure it won't make a huge difference when the car still wants to stall out all the time.

[wrightz28]

If you bought a Wells sensor, i have had some be bad out of the box so keep that in mind.

And, if it were running that rich beofre, the O2 may still be fouled up and causing the "sputter effect". $20 well spent (I always replace mine every tune up, cheap and easy).

A tankful of quality gas and injector cleaner might also help clear thing up too.

[Blaiser17]

Well I just went out to leave to go to work, and the car stalls about 5 seconds after it starts.
The sensor was not a Wells, it was a BWD automotive. So I guess thats a plus. The car has half a tank of new gas I got yesterday and I've been running lucas fuel cleaner everytime I fill up.
I don't know what the problem could be, any other ideas?
Thanks for keepin on trying to help me wrightz28!

I'm going to get a new O2 sensor tomorrow then when I can use my parents' car.

[wrightz28]

Hey no problem. We'll get this thing licked.