Taurus Car Club of America : Ford Taurus Forum banner

1 - 20 of 31 Posts

·
Registered
Joined
·
8 Posts
Discussion Starter #1 (Edited)
Hello, everyone, and thanks for the warm welcome!

Just like the introductory forum says, I have used this forum many a time. You folks are a magnificent wealth of knowledge, and I have researched many of your threads to determine what parts to replace, what shocks to use, why these cars do the weird little things they do, and so on.

This story will be a bit long, so I thank you in advance for reading it all!

To begin: I have a 1999 Ford Taurus 3.0L OHV Vulcan with 77,000 miles. It was kept in a carport for most of its life.

The car has high RPM at start. It used to rev up to the 3,000s+ as I'd just sit in a parking space. Replacing the IAC has helped. If I sit for a while, it calms down and slowly settles at about 1,000. It rarely goes much lower than 900, which is when I shift into gear.

Specifically, I have to let it warm up for a good five to ten minutes before shifting into Reverse or Overdrive/Drive. If I don't, it will "thunk" hard into gear. This used to be so violent that the engine would jerk backward and slam against the hood. It damaged the firewall and snapped the windshield washer fluid line (yeah, really).

Even if the car is warmed up and has been driven for a while, it will do this when shifting into first unless I accelerate veeeeeeeery slowly. And when I say "very slowly," I mean "enraging even to the oldest elderly person who might be following me" slowly. You could walk faster.

Problem Recap: Car has high RPMs at start and takes forever to settle; shifting from cold into R or OD/D is awful; accelerating from a stop into first is also awful

Things I've Replaced: EGR (didn't remember this; checked records, did it last year); PCV (generic), IAC (Motorcraft), motor mounts (heavy ones, and did it again after the engine tried to fly into the cabin), transmission fluid (didn't flush, just replaced), transmission filter (Motorcraft; kept original gasket), oxygen sensor, engine air filter

Things I've Taken It To Specialists For: Looking for vacuum leaks (none found), examining hoses (no issues found), figuring out why the transmission does what it does (more below...)

I've had four or five separate mobile mechanics see it, and they couldn't fix it. I took it to one specialist who diagnosed some of these issues, and I replaced the parts as best they could.

Finally fed up, I did my research, and took it to what is supposed to be the best transmission specialist shop within miles and miles of me. I fully expected to be charged an arm and a leg. I just wanted to be done. I'd do anything. ANYTHING!

... But they told me that there's a transmission cooler leak (is this... possible on the '99 Taurus? Does that little cooler thing leak? I thought maybe they meant a line but they were really adamant), and that the IAC is definitely the culprit. I explained that I already went through several IACs, and that the IAC is a dumb part, but that I'm 100% sure I have the right IAC, recommended by Ford and all.

They then said it must be a computer problem. I replied that the IAC doesn't have any electronics in it, and they said that's fine, sure, but then the car's computer is bad. I argued that it's a '99 and its computer is functionally simple and I really think it must be something else. They disagreed.

So... am I crazy? Am I doomed? Am I seriously just going to, as much as it pains me, accept that this car will always have these problems and just drive it into the dirt? I was willing to throw money at it and that didn't even work...

Thanks in advance for any help you can provide... I'm going to go cry in a corner for a while.
 

·
Registered
Joined
·
716 Posts
To me, its sounds like a vacuum leak. This could be a stuck EGR, or even something as simple as the throttle body plate isnt closing all the way.

Other than that, I would take a can of carb cleaner or starting fluid, and start spraying around those vacuum lines, and intake, and see if you get a blip on the RPM's.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #3 (Edited)
Thank you for replying. I too suspected vacuum leaks, and I wanted to be absolutely sure it was checked correctly, so I'd taken it into a shop for that. They said they'd gone over it a couple of times, and that they could not find it. This doesn't mean I'm dismissing you, though; rather, I have a hard time trusting myself. The longer I've had the car, the less self-trust I've had about fixing it.

What is the relative safety of spraying around with carb cleaner while the engine is running? Fairly good, I hope?

As for the EGR, I'll look into that... I don't know if we have checked that at all!

EDIT: Alas... looks like the EGR was replaced too.
 

·
Registered
Joined
·
8 Posts
Discussion Starter #4
Oh, and the transmission cooler leak thing... am I being "that customer" by doubting the diagnostic? That and their strong feelings about the computer and IAC?

I hate being "that customer" to anyone in labor jobs, because I feel they're deeply disrespected as it is, but... I went through several friggin' different IACs! And it's a dumb part! And it's OEM! And... I'm not crazy, right?
 

·
Registered
Joined
·
716 Posts
The RPM's being so hard will make the engine jump a lot more than it should. Fix one thing at a time here, get the idle under control, and then move on to the next problem.
 

·
Registered
Joined
·
716 Posts
It looks like you were editing the comment about the EGR while I was replying. From my readings on the forum, there is a common problem with the EGR, and you can perform a suck test on it to check for function. Another problem is the Vacuum line to it is in a high heat soak area, so the line looks good, but its heat warped, and leaks.
 

·
Super Moderator
Joined
·
7,685 Posts
And the code or codes present are????? Get the code or codes stored in the PCM and report back.
 

·
Registered
Joined
·
6,573 Posts
Is the IAC valve a Motorcraft brand, if not then you can check codes but you will eventually need to replace it again. I have been there trying to save a few bucks on IAC valves. Aftermarket valves mess up idle speeds and response.


If engine is moving that much you also have broken engine mounts or bolts fell out of the front engine mount. Also the top torque strut must be bad since it should limit engine movement.


Leaking trans cooler should show a drip in the driveway
 

·
Registered
Joined
·
716 Posts
If engine is moving that much you also have broken engine mounts or bolts fell out of the front engine mount. Also the top torque strut must be bad since it should limit engine movement.
I completely forgot about that one.. Yea the engine should not have come anywhere near the firewall, even if the strut was bad. Is the Torque Strut even in the engine bay? Did it possibly rip off the strut tower? I cant imagine it would rip off the engine, thats some pretty high guage steel.
 

·
Registered
Joined
·
59 Posts
1996-99 does not have the "dog bone" torque strut as on 2000-07.

But don't worry, it's easy to install on 96-99 vulcan. I installed on my 97.

Go to JY, gather brackets & hardware from a 2000-07 with vulcan. Purchase new torque strut.

Strut tower will need to have 2 holes drilled to attach bracket the dog bone attaches to. Very easy to do and takes the stress off the motor & transmission mounts.

Late shift:

May be caused by failing shift solenoids on valve body. I'm currently experiencing a similar issue.

From a complete stop I start off in 1, then shift to D at 15mph, then shift to OD at higher speed like 45+mph or freeway and all is fine afterwards.

The torque converter clutch solenoid finally arrived today from RA. Replacing all 5 solenoids next Sunday.

Not difficult - Valve body does not need to be removed, only the cover.

Not costly - All 5 solenoids are under $150 total when using coupon codes from RA and Advance Auto Parts.

Hope this helps

Ray
 

·
Registered
Joined
·
64 Posts
When I got my 1998 with DOHC V6 it would violently slam into first gear, but only started that after I'd paid for it (cash!) and was driving it out of the insurance office lot. :p Took it home, drained transmission, installed new filter. Then the first thing I put in was a full bottle of Lucas transmission fix, then topped it up with the proper fluid. Took a while but eventually it quit slam shifting.

A few months ago I suddenly started to run real crappy, so I installed new spark plugs and wires, cleaned the upper and lower intake, cleaned the IAC passage in the throttle body and upper intake. Installed a new Motorcraft PCV valve, new IAC, and new TPS. Also installed a new elbow hose from PCV to intake. Since then it's wanted to idle way too fast.

NEVER had any codes, even while it was acting like it was running on three cylinders.

A *partial* fix has been to do the idle relearn. Using Forscan and a USB OBD2 adapter I cleared the KAM. Next step is to start it and warm it up. Shut it off for at least five seconds then restart and run for at least two minutes each in these four modes. Use a timer like the stopwatch on a phone. The modes can be done in any order. (Fords with manual transmissions only do two modes, in neutral with AC on and off.)

In park with AC on.
In park with AC off.
In gear with AC on.
In gear with AC off.

Just put your foot on the brake for in gear modes. Don't touch the throttle. Don't move the car. What's supposed to happen is the PCM will 'sweep' the IAC and fuel etc up and down while it learns the settings to make it idle at the right speed. Around the two minute mark in each mode it *should* settle to a proper RPM.

That's worked to pretty well fix the idle speed when it's warmed up, but it did nothing to make it idle properly when cold. Until the temp gauge starts to come up a bit it wants to "idle" at over 1,000 RPM. Yesterday it punched itself up to over 2,000 PRM without my foot on the gas and hit 35 MPH before it warmed up then the RPM dropped to where it should be. It had to have the IAC pulled all the way open to do that. So until I can find how to get it to set itself properly for COLD idle, I have to treat it like it's a carburetor engine with an automatic choke and let it run until the temp gets up a little.

So try sucking a quart of fluid out of your transmission and putting in a bottle of Lucas, then do the idle relearn. Supposedly disconnecting the battery for a while will clear the KAM (Keep Alive Memory).
 

·
Registered
Joined
·
8 Posts
Discussion Starter #13 (Edited)
Hi again, folks! The code was P0402, which I'm sure surprises nobody. I have not tested the EGR valve yet though so I don't have anything to report back yet.

Wanted to reply to this, though:

Is the IAC valve a Motorcraft brand, if not then you can check codes but you will eventually need to replace it again. I have been there trying to save a few bucks on IAC valves. Aftermarket valves mess up idle speeds and response.
Yup, it's a Motorcraft IAC for exactly this reason! I did get an aftermarket one, it didn't work right, and a mechanic both explained to me why and showed me why it wouldn't work.

If engine is moving that much you also have broken engine mounts or bolts fell out of the front engine mount. Also the top torque strut must be bad since it should limit engine movement.
The engine mounts were indeed broken. I replaced all of them. One has broken again and needs to be replaced. Apparently it was a super cheap hollow core rip off. All of the others are sturdy heavy beasts.

The torque strut though... that I don't know. I'm unfamiliar with that and don't remember anyone ever mentioning it. I'll have to read up on it.

Leaking trans cooler should show a drip in the driveway
I thought this too, but they said "it's so small of a drip you wouldn't notice."

Back to checking for leaks and what not as soon as I can. Doing a lot of traveling for work and don't have my own garage or driveway to work in (poor car) so it may be a bit, but I'll update as soon as I can. I'll drive it to an AutoZone parking lot or something if I have time so I can check things out. Thanks again!

EDIT: Just noticed this has gone to a second page, haha! I've read everything else too, including about the solenoids and the other stubborn car needing some relearning, so I'll get back ASAP! Thanks!
 

·
Registered
Joined
·
3 Posts
Just a shot in the dark here but if the EGR checks out check the engine temp with a scantool and see if it's where it should be. A bad temp sensor stuck high or low could cause problems like these.
 

·
Registered
Joined
·
85 Posts
Hi again, folks! The code was P0402, which I'm sure surprises nobody. I have not tested the EGR valve yet though so I don't have anything to report back yet.

Wanted to reply to this, though:



Yup, it's a Motorcraft IAC for exactly this reason! I did get an aftermarket one, it didn't work right, and a mechanic both explained to me why and showed me why it wouldn't work.



The engine mounts were indeed broken. I replaced all of them. One has broken again and needs to be replaced. Apparently it was a super cheap hollow core rip off. All of the others are sturdy heavy beasts.

The torque strut though... that I don't know. I'm unfamiliar with that and don't remember anyone ever mentioning it. I'll have to read up on it.



I thought this too, but they said "it's so small of a drip you wouldn't notice."

Back to checking for leaks and what not as soon as I can. Doing a lot of traveling for work and don't have my own garage or driveway to work in (poor car) so it may be a bit, but I'll update as soon as I can. I'll drive it to an AutoZone parking lot or something if I have time so I can check things out. Thanks again!

EDIT: Just noticed this has gone to a second page, haha! I've read everything else too, including about the solenoids and the other stubborn car needing some relearning, so I'll get back ASAP! Thanks!
Have you not put a scanner on the car and checked once warm, your LT fuel trims at idle and 2500rpm? Have you a scanner that will record what the engine/pcm is doing from start to when it settles down. The measurements should show exactly the area of the problem. EGR codes or indicators can mask issues with the TPS and the throttle body.


You could also have a short circuit in one of the wiring looms. Do you have access to the Ford IDS?


What have you done to check or replace the DPFE sensor?






Tom in Dallas
 

·
Registered
Joined
·
85 Posts
It is likely a dirty or defective MAF sensor. Seen it several times on the OHV motor.
Could be a dirty MAF, but that seems to cause other faults and a defective one will throw a code. Again getting he temp to operating temp and then check LT fuel trips at idle and 2500 wold tell you much, including a graphing of the MAF, but without a code, doubtful it is defective.


TBB
 

·
Registered
Joined
·
85 Posts
It is likely a dirty or defective MAF sensor. Seen it several times on the OHV motor.
Could be a dirty MAF, but that seems to cause other faults and a defective one will throw a code. Again getting the car to operating temp and then check LT fuel trips at idle and 2500 wold tell you much, including a graphing of the MAF, but without a code, doubtful it is defective.


TBB
 

·
Registered
Joined
·
716 Posts
It could also a very dirty butterfly on the throttle body. I saw a video just last night about it causing codes because the butterfly is not able to move/react/close as needed, or as expected by the computer.
 

·
Registered
Joined
·
85 Posts
It could also a very dirty butterfly on the throttle body. I saw a video just last night about it causing codes because the butterfly is not able to move/react/close as needed, or as expected by the computer.
You would more likely find the issue of a throttle being a TPS. A dirty butterfly would show up in the fuel trims and either you would end up with P0171 and 0174 or could go other way and get a P0172 and 0175.
The code P0402 points to the DPFE, but many mistakenly assume it is the EGR- due to the code;
Differential Pressure Feedback EGR (Exhaust Gas Recirculation) DPFE.


https://www.google.com/search?client=firefox-b-1-d&q=dpfe+sensor

Easy enough to find, check and replace.
TBB
 
1 - 20 of 31 Posts
About this Discussion
30 Replies
11 Participants
Jeff K
Taurus Car Club of America : Ford Taurus Forum
A forum community dedicated to the Ford Taurus and SHO models, Mercury Sable and Lincoln MKS. Join the discussions on EcoBoost, aftermarket performance, and more!
Full Forum Listing
Top