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So I got a 97 Buick LeSabre Limited that my grandfather owned since he bought it new. He passed now it’s mine. This is why I haven’t driven it off a cliff.
The issue is that when it starts up it does fine until a min or two later when it’s warmed up, then it bounces above and below 1k rpms for a bit then dies. So I started replacing sensors (map, maf, etc.) literally all the sensors and pcv valve and egr valve have been replaced. So I did a reset and drive cycle twice. Upon reset it runs and drives perfect no issues at all until I turnoff the ignition. Then when I restart it the issue has returned. I then replaced the Computer and did another drive cycle and again it ran amazing. Everything was normal. Shut it off and waited a few minutes and again the issue is back. I’m pretty much at the end of my rope with it.
 

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Also if I keep on the gas at stops it will run fine while driving. If not it’ll die at stops or slow turns.
 

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Sup. You replace the tps throttle position sensor also? Hate to have you throw parts at it because it sounds like a bad maf. A faulty tps will cause some crazy/ scary problems like jolting forward. May not be the root but if you're stalling the only thing i can think is that or no fuel pressure. Check pressure at the Schrader valve. If not those, has it been going through coolant or oil a lot?
 

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Have you taken out your IAC (idle control valve) and seen if the pintle is full of carbon on the tip, and check the bore in the throttle body that it goes into to see if it is clean, if not however you clean it don't just spray cleaner up in there, you don't want to contaminate the MAF thermistors.
You can try to unplug the IAC, it may make the motor idle a bit high, but then it is not going to stall like it has been, and if it doesn't then replace or clean the IAC.
If you replace my opinion is go OE AC Delco, it is more expensive, but worth it when it comes to critical sensors..
ACDELCO 19333189 is the one you'd want.

If you have a multimeter I think you can put it to measure ohms, remove IAC, and test pins 1&2 should see like 10-13 ohms, and test pins 3&4 should be the same.
 

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Another quick fix is to clean the throttle assembly, the throttle plate, and the throttle bore where the plate closes. Also, while holding the throttle plate OPEN, use an old tooth brush to clean the area where the throttle plate closes on to. If you look closely around the base of the throttle housing, there is a "BASE IDLE SPEED SCREW" that can be adjusted manually for higher or lower idle speeds. If your's continues to be a problem at idle, adjust that BASE IDLE SPEED screw for an idle speed that works for you. I have done this many times over all the years I've been wrenching and it does work. However, getting the IAC to function properly is the best way to go. Hope some of this helps....MR GOODWRENCH(Jake)...........
 

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So I got a 97 Buick LeSabre Limited that my grandfather owned since he bought it new. He passed now it’s mine. This is why I haven’t driven it off a cliff.
The issue is that when it starts up it does fine until a min or two later when it’s warmed up, then it bounces above and below 1k rpms for a bit then dies. So I started replacing sensors (map, maf, etc.) literally all the sensors and pcv valve and egr valve have been replaced. So I did a reset and drive cycle twice. Upon reset it runs and drives perfect no issues at all until I turnoff the ignition. Then when I restart it the issue has returned. I then replaced the Computer and did another drive cycle and again it ran amazing. Everything was normal. Shut it off and waited a few minutes and again the issue is back. I’m pretty much at the end of my rope with it.
Hav u tried crank/ cam sensor?hav u ran it for codes cleaned throttle body. How does it drive is the problem @ idle.
 

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Have you taken out your IAC (idle control valve) and seen if the pintle is full of carbon on the tip, and check the bore in the throttle body that it goes into to see if it is clean, if not however you clean it don't just spray cleaner up in there, you don't want to contaminate the MAF thermistors.
You can try to unplug the IAC, it may make the motor idle a bit high, but then it is not going to stall like it has been, and if it doesn't then replace or clean the IAC.
If you replace my opinion is go OE AC Delco, it is more expensive, but worth it when it comes to critical sensors..
ACDELCO 19333189 is the one you'd want.

If you have a multimeter I think you can put it to measure ohms, remove IAC, and test pins 1&2 should see like 10-13 ohms, and test pins 3&4 should be the same.
 

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One other thing I have run into with an IAC valve is the PENTAL can be gunked up enough that it can't open or close properly. Many will say simply replace the IAC. If you want to save a few bucks, you can manually pull the pental up and down while using carb/choke cleaner to all the gunked up areas....this includes the shaft that extends and retracts out of the IAC body. This usually works good. OR, buy a new one. Best of luck.....Jake (mr goodwrench)
 
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