Engine hesitates and sometimes shuts off at running temperature?

1998 OLDSMOBILE CUTLASS
100,000 MILES • 3.1L • 6 CYL • 2WD • AUTOMATIC
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HUDSON23
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Cold start to idle to driving around for a while my car ran fine besides the odometer tripping in and out. When that does it trips my RPMs in and out and hesitates. I have replaced my corroded fuses in the box (all of them) for possibly a better connection. It's only been a day since then and the dash lights seemed to be better even through bumps. Did a thermostat and when it gets to running temperature and fan comes on the charging system feels as if it draws so much from everything and makes the car either hesitant all the way home or once foot off throttle it shuts completely off. Unplugged fan same issues. Before and after the thermo it has hesitated the same just worse since there's better water flow.

I have changed spark plugs, oil, thermo and coolant (for heater in cab issues) so far but hardly can't drive anywhere after the thermo and coolant change once at running temperature. While changing thermo I cleaned the throttle body and IAC sensor (pretty dirty). Ran longer without circulation of water. Not good with electronics and relays but could use some pointers.
Jan 27, 2023 at 3:34 AM
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JACOBANDNICKOLAS
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Hi,

First, does the check engine light stay on while the engine is running? Next, have you scanned or retrieved any diagnostic trouble codes?

When it stalls at operating temperature, does it start right back up, or do you have to wait? If you have to wait, take a look through this link and let me know if it mirrors what you are experiencing.

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

Let me know.

Joe



Jan 27, 2023 at 7:18 PM
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HUDSON23
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Usually only the service light comes on when the odometer stops working on the dash. It will sometimes flicker in and out depending on bumbs or heat. The idling from rpms will work if the speedo stops working but will hesitate with the cooling system when I tries to come on. No, I haven't run codes yet. It's hard to drive it now because I can't get very far without it trying to cut out. It starts right back up but with a little bit of throttle. starts back up without throttle if I wait for a little bit of cool down.
Jan 27, 2023 at 11:00 PM
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JACOBANDNICKOLAS
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The idea that you have to depress the throttle a bit for it to start warm sounds like you may have a rich fuel mixture causing issues. By chance, have you ever noticed any gray or black smoke from the exhaust when you restart it under those conditions?

Let me know.

Joe
Jan 28, 2023 at 8:57 PM
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HUDSON23
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It's not every time I need throttle for restart. It's a hit or miss with it. Depending on if odometer is not working or not with RPMs effects if throttle needs to be played with to start.
Jan 29, 2023 at 3:18 PM
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JACOBANDNICKOLAS
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I'm struggling to find a connection between the odometer and how it runs. When this happens, do the RPMs drop to 0 and the engine responds the same?

The idea that we have two different circuits reacting at the same time leads me to think we have a weak ground. Is everything clean and tight at the battery? If you follow the grounds, are they clean and tight where they attach?

Let me know. Also, let me know if you have had the computer scanned for codes. Since the check engine light is coming on, there should be a code.

Take care,

Joe
Jan 30, 2023 at 3:25 PM
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HUDSON23
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Correct engine (RPMs) reacts with throttle and while driving with or without odometer. Lately like today right now both or glitching in and out and throttle won't react just flicking up and down while the service light flickers on and off like a rave party.
Feb 7, 2023 at 4:51 PM
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JACOBANDNICKOLAS
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Hi,

Thanks for the simile. LOL What a great comparison (rave party). I needed the laugh. There is a wiring issue at some point, but where is the question? Have you tried having the computer scanned to see if there are diagnostic trouble codes stored?

Let me know.

Joe
Feb 7, 2023 at 8:29 PM
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HUDSON23
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Sorry I missed that to put that in. No, I haven't, but I have tried. O'reilly's or AutoZone doesn't have the correct one for mine. Nor does the check engine service light stay on to be able to scan it to read it. I have last night from not able to getting to work it was insane. I scratched the grounds and it's not switching out as bad but the odometer and idling without throttle is still happening at when the cooling system switch comes on.
Feb 7, 2023 at 10:02 PM
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JACOBANDNICKOLAS
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Based on everything happening and how it happens, we must have a weak connection at some point. Have you checked the cluster connectors and the ones at the PCM?

Also, do you have any access to a live data scanner?

Let me know.

Joe
Feb 8, 2023 at 1:29 PM
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HUDSON23
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I have not yet, but once I get home from work in the morning, I'm going to try to take the dash out and grease up the connectors from there and in the engine bay. Anything that has a connector that I can find and get to is going to get sprayed and then greased, lol possibly hope whatever I come across will be working lol just wish I knew exactly what it was for sure to either for sure fix or clean for a for sure know that I what stand me again on the road.
Feb 8, 2023 at 3:05 PM