Problem with 3.0 flex hesitation

00RangerXCab · Sep 22, 2016

Morning, I have what I think is a tough one.

My 00 3.0 flex ran warm the other day ( just a hair over mid nothing too high (if it went higher I didn't see it). Come to find out I had a bad upper hose. Fixed it and we are now good.

My problem now is when the truck idles it's perfect... when it drives it's perfect. .. but when I let off the gas it stutters a bit. It never shuts off and if I give it a tap of the Gass it goes away. Like in said it doesn't shut off, it idles perfect and it drives perfect. Occasionally at highway speeds when it shifts to od or if I let off the pedal u will feel the shutter.

There is no check engine light and the shutter isnt bad but it's there and it bugs the mess out of me (I keep Ole girl running the best she can).

I was thinking maybe a slight vacuum leak but I'm not sure. Any help would be greatly appreciated. Thanks!

RonD · Sep 22, 2016

If you have an automatic, when your engine runs hot it also causes the transmission to run hot, trans cooler is in the radiator.

The shutter could be engine related but could also be trans related, i.e. torque converter lock up.
When you "let off the gas" the torque converter should also release in most cases, to allow smooth shifting and stopping.
Simple test is to shift in to Neutral before stopping to see if shutters stop.

The computer knows "gas pedal" position from the TPS(throttle position sensor), so that is another suspect, since computer controls engine and transmission(automatic) a TPS problem could effect engine fuel or torque converter lock up.
TPS is simple to test with a volt or ohm meter, sensors rarely fail so never replace sensors, test them.

00RangerXCab · Sep 22, 2016

RonD said:
If you have an automatic, when your engine runs hot it also causes the transmission to run hot, trans cooler is in the radiator.

The shutter could be engine related but could also be trans related, i.e. torque converter lock up.
When you "let off the gas" the torque converter should also release in most cases, to allow smooth shifting and stopping.
Simple test is to shift in to Neutral before stopping to see if shutters stop.

The computer knows "gas pedal" position from the TPS(throttle position sensor), so that is another suspect, since computer controls engine and transmission(automatic) a TPS problem could effect engine fuel or torque converter lock up.
TPS is simple to test with a volt or ohm meter, sensors rarely fail so never replace sensors, test them.

Thank you for the reply

First. If I do put it and neutral and the skip goes away how do I go about ficong the issue.

Secondly. I have a dmm and I have used it for car stereo but how do I use it to check the tps and what am I looking for?

Thanks again!

00RangerXCab · Sep 22, 2016

OK found what I'm hoping is the issue. On front of the plenum is a square sensor with a plus and 2 tits facing down with a vacuum hose on each tit. One of the tits is broke off with the hose hanging

What is this sensor

00RangerXCab · Sep 22, 2016

Ok, I have found out the sensor is a DPFE sensor. Would the hose being broke off explain my issues?

Thanks!

RonD · Sep 22, 2016

No, probably not, the DPFE sensor hoses go to exhaust/EGR tube.
But you should fix it, and it is odd your CEL(check engine light) is not on???

That sensor tells the computer if EGR valve is opening and how much exhaust gas is flowing into the intake.

If CEL is not working then you need to get the Codes in computers memory, write them down, that could tell you what the problem may be.
There are transmission codes as well as engine codes so could be a clue in there.

Get a sewing pin(needle)
Find the TPS
It will have a 3 wire connector
Pierce the Center wire with the sewing pin
Set Volt meter for 20volts DC or just DC Volts
Turn on the key/engine off
Put black meter probe on battery negative or engine Ground
Put Red meter probe on sewing pin, you should see .69 to .99 volts, under 1 volt

Slowly open throttle manually and watch the voltage, should steadily climb up to above 4.49volts when throttle is wide open.
Then slowly close it and watch voltage drop

If voltage jumps around at a certain spot then replace TPS it has a dead spot.
If voltage is steady, no jumping around, then TPS is good

ratdude747 · Sep 22, 2016

Did you bleed the cooling system correctly? The 3.0 can be a real pain to bleed, and I have heard of air in the cooling system causing weird issues like that.

Problem with 3.0 flex hesitation

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