2.9L stumble at low rpm only ?

[Dusty_Ranger]

k so for the last little while my truck has been stumbling at low rpm only, as in stubles look at the tach and the needle is bounching around, only dose it under light to medium throttle, ive done plugs and wires, cap and rotor, fuel filter, IAC, grounds, im sure the tps is ok but im going to check it still, and it mostly dose it till the truck warms up? any idea's im soooo completly stumped, help greatly apprieciated

 

[jhammel85]

Hmm....do you know how the fuel pressure is when this is going on? How's the O2 sensor?

My truck did this from time to time before I switched out the champion plugs I had it in for good ol Motorcrafts...Hows the gap on your plugs?

BTW, nice truck

 

[Dusty_Ranger]

fuel preasure is good and plugs are some fusion +4 cant adjust the gap on them, not sure about the oxygen sensor tho

 

[2.9XLT]

You should have your ignition module tested, the tach bouncing around can be caused by that.

 

[Dusty_Ranger]

ignition module? as in TFI module?

 

[Big Jim M]

That engine should have two temp senders. One of them is for the gauge in the truck and the other tells the temp to the computer. If the computer one is telling lies to the computer it will run badly when cold... as the sender is telling the computer the engine is already up to temperature. Check it out.
Big JIm

 

[Dusty_Ranger]

ill try that it only seems to do it when it cools down, mornings and evenings

 

[bronco_lou]

Why when these trucks have a computer that can tell you if something is wrong, people don't pull the codes? Pull the codes and see what the computer says.

Louis

 

[DisturbedMXer8]

Why when these trucks have a computer that can tell you if something is wrong, people don't pull the codes? Pull the codes and see what the computer says.

Louis

Because this truck is OBDI, they don't trip codes for every little thing like OBDII systems do.

 

[Dusty_Ranger]

so i got codes 53 and 63 with both are throttle position sensor issues , 53 is tps sensor above maximum range and 63 is tps voltage too low phuck im stumped i guess ill have to try and swap out tps sensors

 

[bronco_lou]

put in a new one and see if that don't cure the problem, make sure you get one for your year of truck.

Louis

 

[bronco_lou]

Because this truck is OBDI, they don't trip codes for every little thing like OBDII systems do.

Are you sure about this?

 

[Psychopete]

Test it with a cheap analog volt meter..

 

[Dusty_Ranger]

swaped out the tps now im getting codes 29 87 and 95

29= veichle speed sensor fault (speed sensor on the speedometer output has never had wires going to it)
87= primary pump circut failure (NEED HELP WITH THIS ONE)
95= fuel pump circut open (dads truck runs fina and has this code)

 

[bronco_lou]

swaped out the tps now im getting codes 29 87 and 95

29= veichle speed sensor fault (speed sensor on the speedometer output has never had wires going to it)
87= primary pump circut failure (NEED HELP WITH THIS ONE)
95= fuel pump circut open (dads truck runs fina and has this code)

Did the new TPS help any?

I would clear the memory, then run it and rerun the codes. After I put the 4.0 in my truck the computer it tossed the primary pump circut failure error. I cleared it and it never came back up.

Don't clear it by removing the battery, once you start the test and it starts flashing the codes unplug the tester, that should clear the codes.

Louis