no codes anymore... still won't idle!!! I need help asap

[bigredneck61088]

The story is... 98 4.0 ohv, throwing p0171 and p0174 both banks, both lean, changed MAF, still threw the codes, cleared em. Now the codes haven't been back but the truck has gotten progressively worse running and will not idle, lopes real bad. Fuel Pressure and filter in fine condition.

Then I replaced the upper intake gasket(rubber) and the lower(under the fuel rail) as per on the sites. No change after that!! Haven't had the codes come back yet. I am stumped and i need to get back to work, any help/input appreciated. I have scoured for vaccum leaks and cannot find any. PCV or IAC maybe?? I just need another direction to go i am stumped.

I also replace the plugs and wires and no change either

 

[jlburkey]

Maybe the throttle position sensor has failed or is not calibrated. Can you keep it running if you keep foot into it?

 

[multiranger]

The story is... 98 4.0 ohv, throwing p0171 and p0174 both banks, both lean, changed MAF, still threw the codes, cleared em. Now the codes haven't been back but the truck has gotten progressively worse running and will not idle, lopes real bad. Fuel Pressure and filter in fine condition.

Then I replaced the upper intake gasket(rubber) and the lower(under the fuel rail) as per on the sites. No change after that!! Haven't had the codes come back yet. I am stumped and i need to get back to work, any help/input appreciated. I have scoured for vaccum leaks and cannot find any. PCV or IAC maybe?? I just need another direction to go i am stumped.

I also replace the plugs and wires and no change either

Just because the CEL isn't on doesn't mean there are no codes... If you can post the data on the O2 sensors... I would like to see the Milivolts..Other than changing a few gaskets what else have you done to correct the issue? or what type of trouble shooting have you done?

 

[Big Jim M]

hmmmm

The story is... 98 4.0 ohv, throwing p0171 and p0174 both banks, both lean, changed MAF, still threw the codes, cleared em. Now the codes haven't been back but the truck has gotten progressively worse running and will not idle, lopes real bad. Fuel Pressure and filter in fine condition.

Then I replaced the upper intake gasket(rubber) and the lower(under the fuel rail) as per on the sites. No change after that!! Haven't had the codes come back yet. I am stumped and i need to get back to work, any help/input appreciated. I have scoured for vaccum leaks and cannot find any. PCV or IAC maybe?? I just need another direction to go i am stumped.

I also replace the plugs and wires and no change either

I'm thinking IAC.. Idle Air Control is the part that makes it idle.. At best a good cleaning might help.. At worst a brand new one might get it back to normal running..
A bad PCV will force oil out the rear main seal.. If it ain't leaking real bad that should be Ok. It NEVER hurts to install a new PCV device.
Big JIm