Question 2004 Pace Arrow 36B bad running 8.1 Vortec

[latech]

Also , there is a procedure to perform called a "Cam/crank sensor correlation relearn" procedure.
It wont run if there are active misfires happening
But , you will want to do this procedure if your coach has any miles on it at all.
I have seen 496 set misfire codes because of cam/crank correlation problems. Kind of a catch 22 there sorry

Post your code
Then probably on to the intake gasket.
If it has an intake leak , it is wacking the fuel trim ( adaptive strategy ) all over the place so....

 

[DHudson]

This won't fix your O2 codes, but we used to get a lot of trucks that would go into limp mode with no codes. Just like yours, kill it and restart would run fine, sometimes for a month or more. Usually got worse and worse. Majority of the times, a NEW throttle body fixed it. If you got this route, do not be a rebuilt unit. You will be buying some else's problem. Only buy a new unit. And like before buy quality Delco, Delphi, Standard Ignition, NOE (Dorman) Napa, or TEE Napa.

 

[Newton36B]

I would not rule out an intake leak. Since only 1 bank is affected, I would start there. Those are known for intake plenum gasket leaks
A code for one bank wont be a MAF sensor as the MAF feeds both banks so...
Maybe change the intake plenum gaskets first , and see if that does it.
Post the code number EXACTLY as it appears . Plenty of O2 sensor codes ,they all mean something a little different

I just saw the second code, both are as follows : PO131 02 sensor circuit low voltage Bank 1 sensor 1

PO151 o2 sensor circuit low voltage bank 2 sensor 1

Thanks

John

 

[latech]

Since both banks are doing the same thing, it very well could be a MAF
Intake leak could be it also.
Maybe the MAF is dirty or contaminated.
You should look at the MAF to see if the little sensor inside ( thermistor) is covered with schmutz.
You can clean them with an artist paintbrush and brake cleaner by spraying it and GENTLY brushing it loose with the brush.Then spray again to rinse the sensor.
If it is dirty ( which is likely/possible) that would caus ea lean condition like you are seeing.
Any air leak in the intake /intake hoses after the sensor can also cause the issue.Look for holes in the air intake tubing.
You may want to change the intake gaskets just to rule it out. But check the MAF first.

 

[DHudson]

If the intake is leaking, on one side, you will be getting too much air in those cylinders and the O2 sensors will get a faulty reading. If there is a plastic cover on the engine, remove it. Start the eng.jine and spray water from a spray bottle along the mating surfaces. If it start missing you have a leak. I always use carb cleaner will will speed up the idle. But hate to recommend that because of the possibility of fire.
But, I think you have 2 problems.

 

[Newton36B]

Since both banks are doing the same thing, it very well could be a MAF
Intake leak could be it also.
Maybe the MAF is dirty or contaminated.
You should look at the MAF to see if the little sensor inside ( thermistor) is covered with schmutz.
You can clean them with an artist paintbrush and brake cleaner by spraying it and GENTLY brushing it loose with the brush.Then spray again to rinse the sensor.
If it is dirty ( which is likely/possible) that would caus ea lean condition like you are seeing.
Any air leak in the intake /intake hoses after the sensor can also cause the issue.Look for holes in the air intake tubing.
You may want to change the intake gaskets just to rule it out. But check the MAF first.

I've got a whole new list of things to check. Thanks

 

[Newton36B]

If the intake is leaking, on one side, you will be getting too much air in those cylinders and the O2 sensors will get a faulty reading. If there is a plastic cover on the engine, remove it. Start the eng.jine and spray water from a spray bottle along the mating surfaces. If it start missing you have a leak. I always use carb cleaner will will speed up the idle. But hate to recommend that because of the possibility of fire.
But, I think you have 2 problems.

I will give this a try, I thought the intake leak would run bad all of the time ?

Thanks

John

 

[DHudson]

I will give this a try, I thought the intake leak would run bad all of the time ?

Thanks

John

May not, if it's to REAL bad

 

[Newton36B]

May not, if it's to REAL bad

Tommorow were going to install a new MAF sensor and see what effect that has, the problem is that I have to drive it about 75 miles to get to act up !

 

[DHudson]

May not, if it's to REAL bad

"Not" real bad