intermittent running problelms

[ron55]

My 2004 8.1 chassis run ok for a couple of miles then doesn't go into limp, go below just idel and surges at a low rpm and won't pull itself. after it sets a while 5 minutes it will start up and go but it doesn't last long and does the same thing again
1.throws these codes P0131, low v to o2 sensor, P0151, low v to 02 sensor and U0107? I think this a low v to what I don,t know?
2. fuel pressure from fuel rail is 62psi constant, during trouble period the pressure gauge needle shakes a little 60 to 62
3. the pressure is holding at 60psi with the engine off
4. It act like it not getting fuel but the rail is showing 62 psi
5. Not smoking like its flooded
help!

[DriVer]

Quote:

Originally Posted by ron55 My 2004 8.1 chassis run ok for a couple of miles then doesn't go into limp, go below just idel and surges at a low rpm and won't pull itself. after it sets a while 5 minutes it will start up and go but it doesn't last long and does the same thing again ..... help!

The best thing to do would be to get it diagnosed with a Tech II. The T2 can scan your system for specifc errors and get you back on the road quickly.

[ron55]

I am a long way from a service center.
evidentely it is low voltage to the throttle position control.
Driver does the 2004 model have the TAC in the ECM or does it have a seperate TAC. It not communicating with each other due to low voltage (what is causing that)
Good battery the alternator is putting out 14.1 v
I am sure the throttle is not opening is my problem
It seem to run Ok until I have to mash the throttle and then it begins to fail

[DriVer]

Quote:

Originally Posted by ron55 IDriver does the 2004 model have the TAC in the ECM or does it have a separate TAC. It not communicating with each other due to low voltage (what is causing that)

I was thinking either the TACM or the TPM. These devices are separate from the ECM. That said I really would not want to make these DX recommendations because these things cost money and I would not want you to throw money at this thing w/o getting a good DX from a T2.

Make sure that all those connectors under the dash are plugged in.... if you can get to them.

[ron55]

I know where the TPM is but where is the TAC located?

[JonBrazel]

The TAC module is located just to the right and forward of your emergency brake pedal mounted vertically on the steering column support. It has two plugs going into it. Generally if you follow back from your OBDII plug you will find it. Start by checking to make sure you have good connections there.

[DriVer]

Quote:

Originally Posted by JonBrazel The TAC module is located just to the right and forward of your emergency brake pedal mounted vertically on the steering column support. It has two plugs going into it. Generally if you follow back from your OBDII plug you will find it. Start by checking to make sure you have good connections there.

Jon, Thank you! I was getting to it but ya beat me to it. I already had that module replaced once at Lazy Days.

[TrekPR]

If you don't think you are getting fuel you might try the fuel filter. If it is clogged you would still have pressure at the rail but not the volume when you hit the gas. The pressure may stay the same if you can't draw a vacuum on the line. I might be showing my ignorance on this but it might be worth a try.

[Full-Timers]

Sounds like the time I had a bad Crankshaft Position Sensor. This is common and there is a recall on the same one they put in the trucks. Don’t know why they didn’t recall the ones in the motorhomes. The replacement I got was definitely different. Mine however had a code P-1518.
Here is a link to the post. Crank position failure?

[pkmesser]

DTC U0107
"Lost communication with Throttle Actuator Module."

Your codes defined the problem, solve this, and you're probably good to go. (It is highly probable that it is an electrical issue, not hardware. As it is a communication issue, connectors and wire is most suspect. Others have already pointed in this direction, but this code explains why no power, you are pushing on the footfeed, but the throttle is not opening.)

BTW, a friend, when I asked him about a trouble code, filled me in, put the code in your search engine, and you will find out what it is, along with a lot of trouble shooting information from various forums.

[justimagination]

...........Had you recently just filled the fuel tank? JMHO since it's intermetent. Electrical issues USUALLY don't correct it's self by setting for a few minutes. Sounds like fuel issues to me. Good luck and travel safe.
David G.

[DriVer]

Quote:

Originally Posted by justimagination .... Electrical issues USUALLY don't correct it's self by setting for a few minutes.

David, On a Workhorse I have found that sometimes they do. Turn the key off, wait a few moments and fire it back up and more than 50% of the time the issue has disappeared. (I won't swear on a stack of bibles that the issue won't come back .. but in that case if the event is repeatable ... it's not usually intermittent)

[ron55]

Seems ok now after two test runs.
Cleaned the battery connections
Un plugged looked and repluged at all throttle related connections
The TAC connection seemed loose so I zipped wire tie that up tight
cleared the codes and test ran again to day so I am headed to Colorado to climb some 14ers. Thanks for your help

[DriVer]

Quote:

Originally Posted by ron55 Seems ok now after two test runs. Cleaned the battery connections. Thanks for your help

I'm glad it worked out for you!