1999 Mountaineer Kickdown/downshift/passing gear issue

[austinjholt]

Hey Everyone!

I am new to the boards; just bought my first Ford from a friend, and it luckily only has a few issues, one of those being related to the one mentioned in this thread.

Any help is seriously appreciated!


1999 Mountaineer, 5.0, auto: with what I believe is a 96 Ford Explorer 5.0 motor, which was rebuilt and placed in the car before I bought it.

Problem/Background:

In first gear,(from 0) I can floor it, stays in gear till a pretty high rpm, shifts into second, third, fourth, 5th, etc. No problems. Runs like a champ..solid shifts, no slipping, etc.

However, when I floor it from really any speed, it will only downshift what feels like one gear, instead of 2, so there is very little acceleration/passing power.

Anyone ever experience this?

The other issue I have is a cylinder 6 misfire - replaced plug, wire, packs, etc - still showing code. Could this be related?

I have thought through/researched a few solutions:

Bad tps
Bad speed sensor
Bad pcm?

What do you all think? Again, thank you in advance!

Blessings,
Austin

 

[koda2000]

the 5.0's auto trans is a 4 speed, not a 5 speed. if i remember correctly someone else reported having this problem and it turned out to be the TPS.

 

[rs2k]

Do you ever get any hard down shifts while slowing down?

 

[austinjholt]

Do you ever get any hard down shifts while slowing down?

Negative.

 

[Turdle]

The transmission will not downshift to 1st at speeds over 30 MPH.

 

[austinjholt]

The transmission will not downshift to 1st at speeds over 30 MPH.

If I floor it at 20, it won't go down 2 gears

When I'm going 60 I'll go to WOT it sometimes won't even go down 1 gear and accelerates SUPER slow. Almost dangerous slow when I am getting on highway.

 

[imp]

Trouble codes? If we knew what the PCM "looks at" mainly, in determining it should downshift, we might have more insight into what the cause is. Sounds like it's not a problem internal to the transmission, I think.

My guess is that the PCM program downshifts based on engine speed and load, compares those to what's being demanded by the driver, which is Throttle Position determined, so TPS seems possible. But you'd think bad TPS would show up other problems, slow accelerate, bad idle, jerky accelerate, etc. Check TPS voltage, compare to charts. imp

 

[rs2k]

Have you checked the fluid level in the tranny?
Have you tried resetting the computer by leaving the battery undone for about 10 mins?
Are you getting any other drive-ability problems?

A misfire should be pretty noticeable. I don't think the PCM will throw a misfire code unless it happens twice in a row. I think it's also possible for the PCM to be off a cylinder. If the PCM tells you it's 6 it might actually be 2 or 5. I'm not 100% sure on that though. Can anyone confirm?

Can you hook up a vacuum gauge and give us the readings and needle movements?

 

[austinjholt]

Trouble codes? If we knew what the PCM "looks at" mainly, in determining it should downshift, we might have more insight into what the cause is. Sounds like it's not a problem internal to the transmission, I think.

My guess is that the PCM program downshifts based on engine speed and load, compares those to what's being demanded by the driver, which is Throttle Position determined, so TPS seems possible. But you'd think bad TPS would show up other problems, slow accelerate, bad idle, jerky accelerate, etc. Check TPS voltage, compare to charts. imp

There is a slight rough idle, mainly only at idle, or at the lowest rpm once the car hits overdrive, at low speed. This happens after I've driven the car for 15 minutes or so. Once it gets out of that rpm range/load, the motor is smooth as silk.

The only code the motor is throwing is the cylinder 6 misfire.

Tomorrow, I will go ahead and check/swap the TPS sensor and see if that gets me anywhere.

I did check fluid level.
I did reset computer properly.

I will try and get a vacuum gauge on it tomorrow as well.

Thanks a ton for the input - I will report back once I change out the sensor.

Austin

 

[austinjholt]

Trouble codes? If we knew what the PCM "looks at" mainly, in determining it should downshift, we might have more insight into what the cause is. Sounds like it's not a problem internal to the transmission, I think.

My guess is that the PCM program downshifts based on engine speed and load, compares those to what's being demanded by the driver, which is Throttle Position determined, so TPS seems possible. But you'd think bad TPS would show up other problems, slow accelerate, bad idle, jerky accelerate, etc. Check TPS voltage, compare to charts. imp

Replaced the TPS - no change at all.

 

[rs2k]

Have you been able to try hooking a vacuum gauge up to it? It could tell you a lot.

 

[austinjholt]

Have you been able to try hooking a vacuum gauge up to it? It could tell you a lot.

I haven't, however, I have learned 2 pieces of info that may help solve both issues I'm having:

1. The transmission will downshift properly if in cruise control.

2. In regards to #6 cylinder misfire: at 60-61 mph in overdrive, the CEL will blink around 10 times then stop. It only blinks at that speed and in overdrive. Averaging 14.5 mpg.

Thoughts???

 

[drako]

Looks like this post is a little old, but im hoping the issue was found.... any chance you could share the fix?

I have a 2005 Merc Mountaineer and its pretty much duing the same thing. I have gone through the plugs and all the coil packs, i aslo replaced the TPS.

At normal speeds it will shift ok but once you are at speed and you mash it to the floor it will tank, even going as far and hiting the rev limiter and still wont shift. The CEL will come on, blink for a bit then stay solid.

Normaly the flashing CEL means a missfire but all the computer says is random missfire on the code. I can reset the CEL and it will stay off till you go to pass or mash the pedal to the floor again.

Thanks in advance for any feed back