No end-of world virus stuff, nor gubmint takeover, nor Rothschilds assuming full control of world economic order this time - just car help.

Note: I can't put this in the 'Trucks 'n 4-wheel Drives" forum, 'cause this vehicle is neither . With that technicality out of the way, here's what's up:

* 2005 Ford Taurus SE, 3.0 OHV Flex-Fuel "Vulcan" Engine
* Just under 180K miles
* Owned by kid #N, who's 5 hours away (I'm tryna help him remotely)

Car has begun to stall occasionally when first placed into Reverse, or Drive. He's learned to feather the accelerator to keep it going if he feels it starting to crap-out. Once it gets going, however, it runs fine, accelerating well, holding constant speeds either on streets or the interstate. He's gotten no CEL. An auto parts store just ran some tests, and found no codes, a good battery (12,5V), and a properly functioning alternator.

He reports that it idles well if left in Park. When the AC compressor engages, the engine surges somewhat (as expected), but that it quickly settles back into a regular idle.

Maintenance has been regular and competent. Repairs have been done as needed. The current state of the mechanicals:

* Motorcraft plugs, installed at 110K
* Autolite wires at 140K (damned squirrels)
* Motorcraft coil, 165K
* Alternator replaced 120K
* IAC replaced 150K
* Intake Manifold Runner Control gasket replace 115K
* MAF sensor cleaned 6 mos. ago, when air filter was replaced
* Throttle body cleaned at same time
* Fuel filter replaced at 110K
* AC compressor replaced (the 2nd replacement ) at 155K


Some ideas I've had:

1) Vacuum leak. Hey, it's a Taurus, right? They're [intercoursing] born with vacuum leaks.

2) IAC. Again, it's a Taurus. One can either buy more Motorcraft IAC's and get maybe 30 to 50K out of 'em, or buy another brand that won't work right out of the box. It's a damned racket.

3) Electrical fault/short. Yup, it's still a Taurus. Perhaps it's a rusty spot at a ground, or a pinched wire somewhere that shorts as the car moves and the engine shifts. When his 1st AC compressor went, the clutch was trashed & kept tripping a fuse that also controlled the Keep-Alive Memory. He could replace the fuse, & the car would run well so long as the AC compressor wasn't activated. As soon as it was, though, the fuse would blow, & it would idle like [excrement], and usually stall.

4) Worn Spark Plugs. I believe we put in Double-Platinum plugs at 110K, that are purported to be good for the 100k the service manual spec's. Then again, when we removed the original plugs (color coded with paint dots) at 110K, they were worn to the point where we were amazed that the car still ran, and that the CEL wasn't lit up. Could it be that they're worn again after nearly 70K miles, and the big gaps are forcing the ignition system to suck-up hella power to make a spark that'll jump those Rosie O'Donnell gaps?

The kicker is that he's looking to sell the thing in the near future, and wants to put no $ into it, if possible. If #4 above were the case, theoretically he could pull the plugs, smash the straps back down toward the center electrode to the spec'd gap, and be out nothing more than the amount of skin he left under the hood trying to reach those [maternal fornicating] rear bank plugs.

What sayeth the peanut gallery?

- Are we barking up the wrong tree?
- Are we [urinating] up the wrong rope?
- Are we pounding sand down the wrong hole?

Let's see if our collective brain trust can figure this out.

Thanks in advance,

FC

Fuel pump. That’s what it was when two of my Ford pickups of approximately the same vintage started doing the same thing.

Yikes. Those aren't free, are they.

FC

No but not too bad. Last one I had done was under $200. Depending on where the tank is he might be able to peel the carpet up in the trunk and sawzall a hatch in the floor to change it without dropping the tank. Not sure about a car but it works on Broncos.

Loose gas cap?

I'm not kidding.

Maybe he could get lucky, & it's just a wonky relay. I'll have him thump it with a screwdriver, or perhaps swap it with a different one.

Hey, it's cheap, it's easy, & it just might work. Kinda like me...

FC

Has the crankshaft position sensor been checked ?
They can cause problems like you are describing and not set fault codes.

Dump in 2 cans of sea foam into the gas tank.Might get lucky

IAC can cause problems and not set codes. And sometimes put one in and a second one to get a good one.

You're probably dealing with an intermittent OPEN circuit, not a short. Shorts blow fuses. Opens are caused by dirty, loose connectors or wires with broken or corroded strands inside the insulation . With the engine idling in park and the parking brake set, grab any wire harnesses you can reach and do a "wiggle test"- - - -shaking and pulling on the harness like happens when the car is put into gear and the engine torques on its mounts. When you find the one with the loose connection, the engine will stall. Find and fix the bad connection or broken wire that's reacting to torque. Fords are notorious for getting bad connections and the wiggle test is the first thing they recommend in factory service manuals. I've been finding electrical problems other mechanics have given up on since the early 1960's and this is a test I use a lot. Good luck!
Jerry

We need some of the drill bit Mensa club to migrate over help FC out. That’s an untapped brain trust.

Sorry I’m no help, that’s newer than anything I drive.

There are a ton of " could be's " in this case. If its possible find someone with a scan tool that knows how to use it and try to capture whats data is dropping out when it stalls. Does it do it cold and hot? Some of the "could be's " could be EGR, TPS ? Good luck.

Those platinum plugs were discouraged by ford guys i know. They said buy the cheapo motorcraft or off brand. Said you get issues like that.

Has fuel filter been mentioned? In my 89 was easy to get to

Disconnect the battery for a few minutes......reconnect and try again.

May not work, but a cheap try.

Has worked on other cars with similar symptoms. Fine in park and neutral, bad in drive.

Call that outfit in the TV ads who bring you a new car on a flatbed and haul your old one off. You don't even have to leave your self-quarantine.

Best option is to cut your losses and buy a Toyota.

My guess would be the TPS.

^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

This here's your huckleberry, most likely !

My .02, as a garage owner.

Definitely not vacuum leak - added air after MAF, engine would idle higher & never completely settle to normal.

Fuel makes absolutely no sense either.

By the way, our shop has never changed a fuel pump in a ford truck. Fuel module driver always.

Possible mass air flow sensor, if you can trace to this, by cleaning thus eliminating problem, buy NEW, bitches to clean & maintain (cleaning is ever only a temporary solution).

Clean & reinstall throttle plate/body.

Not IAC either

Damned fords hardly ever set a check engine light !!!

Good luck FC !

1 can per tankful of gas. Seafoam can cause more harm than good if overdosed.

Thanks, HrL & 99's. My gut kinda tells me this is the most likely. His brother's 04 had the Driver's window dead for nearly a year (thankfully while fully UP) while we tried to figure it out. It had been working fine, and the fuse was good. It took me a while to notice that the dome light was also out, so I checked THAT fuse. When I found it was burned out, I figured I'd fix at least one of his problems, but surely enough, the [eternally damned, porcine fornicating] driver's window motor started working again! Who the hell would put THOSE 2 things on the same circuit? And even if they did, why couldn't they label it better???

It's awfully frustrating that they couldn't have [bleep] [excrement] like this figured out by the 4th generation of the damned car.





That's been the plan for several years. This Taurus was what he could afford at the time, and since he paid for it in full, he's made due with it. Now he just needs to get it running well enough to sell it.


Thanks for the ideas. Keep 'em coming!

FC

might be idling to low, had that problem with my truck. adjusted up to 800 rpm and no more stalling.

Sounds like my old Ford every time I got a tank full of crappy gas.
Nothing that a 2 dollar bottle of HEET® didn't cure, kept one in the glove box, always.

UPDATE:

He sent a video that showed the engine bay, with the motor surging noticeably at idle. Then he turned on the AC, and the video showed the tachometer swinging wildly from 500 rpm to 1500 rpm.

He removed the NAPA IAC he’d installed in 2016, and replaced it with the original Motorcraft one that he had hung onto for some reason. Voilà - a steady 850-ish rpms both with AC, and without.

In this particular instance, his packrat proclivity seems to have paid off. I think he retained the original IAC in case it was not the reason for his engine malfunction back then. That did turn out to be the case: ‘twas a disintegrating AC clutch that shorted out a fuse for the keep alive memory.

In any case, he’s got it running at no extra expense, and with nary a nick or cut on his hands. He’s crossing his fingers that this fix gets him through, and doesn’t turn into one of those famous, “well, it ran well for 3 days, but then...” repairs that Taurus are known for.

Thanks to everyone for the input,

FC

I was gonna say take a chopsaw and cut the piece in half through the crane, barrel and trigger and throw both halves in the trash but then I realized it wasn't that type of Taurus.

I’ve not had good luck with those kind, either.

FC

Happy ending!

Sounds like he's got a head on his shoulders too.

Unless the plugs are OE spec'd plugs I totally agree. My old V10 truck takes basic cheap Motorcraft plugs. Don't do off brand.
Someone mentioned Sea Foam and I kind of agree. It won't hurt and could try cleaning the MAF sensor if it has one. May see if you could check or clean out the EGR valve.