Rough idle, stalling, code P1633

2002 FORD TAURUS
215,000 MILES • 3.0L • V6 • 2WD • AUTOMATIC
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SHASTAJOY
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Rough idle at times, will spit and sputter and shut off, but then after awhile will be fine. There is new alternator and battery and power steering pump, plugs changed. Code that has come up was P1633 mod. I’m not very knowledgeable with mechanics but got brothers that lend help with what they know but we are stumped. It shuts off and then spins the crank but does not try to fire. I have three kids and can’t be stranded with them so I need to fix this.
Aug 12, 2019 at 8:36 PM
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JIS001
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Hi and welcome to 2CarPros. With the code you have you need to check fuse #22 in the engine compartment. If the fuse is good.then remove the engine control module connector and with key on engine off at pin #55 pink wire with light blue stripe check for battery voltage if voltage is present, wiggle the engine harness around to see if voltage drops off. If it does then you have a wiring issue. If it doesn't then the PCM has an internal fault.

I attached some images and highlighted the pin location and fuse location. You may have other issues bit the PCM issue needs to be addressed first. If the keep alive memory loses voltage it is acting as if you disconnected the battery. When the battery is disconnected then the memory resets and a drive cycle needs to be performed to relearn the values programmed. With it resetting all the time the computer gets confused.

In my experience, and since the fuse is shared with the A/C and you have not mentioned no A/C issues, the PCM is most likely bad. Let us know what you find with the diagrams and links posted.

https://www.2carpros.com/articles/how-to-check-wiring

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Aug 12, 2019 at 10:28 PM
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SHASTAJOY
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The air conditioner pulley is seized up so I had to run my belt to bypass it, so it’s not working. But now the running (stalling) is worse. I changed the plugs and wires this morning, I had help and it was done right but now it’s worse. It’s getting spark but not firing and backfiring. I can’t get it to stay running long enough to shift it into gear let alone move from the spot it’s in, so now I’m unable to drive it for diagnostic. My brother came and checked it out but is stumped too. He thinks it’s possibly a clogged fuel filter. He had tapped the filter then started the car, it fired up and then without anyone touching it the car revved up like suddenly it was getting gas and then died out again. The fuel pump is working. The car has had a number of things replaced in fact and the head gaskets are good.
Aug 14, 2019 at 9:41 PM
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JIS001
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It almost sounds like a bad idle control valve. Carbon inside can cause the slide valve to stick where it idles too low and stall or get stuck at high idle. Try removing the idle valve and soak it up with carburetor cleaner to clean it. Usually helps but most likely you will need a new one. Here is a link on how to service the idle air valve. Try it and let us know if it helps.

https://www.2carpros.com/articles/idle-air-control-valve-service
Aug 14, 2019 at 10:06 PM