I have done everything. E150 4.2. Pulled plugs and 5 & 6 look like they are running rich. Code 0175 (bank 2 rich) comes up at low rpm and just starting to move. Truck will stall alot at idle. High speeds the truck runs fine. I have visually looked at all vacuum lines and as far as I can see. they are old but fine. Is there a way to check for a leak other than replacing all of the lines.

 

Generaly vacuum leaks will cause a lean condition - do you by chance have a injector that is leaking?

David

 

Do you mean leaking into the cylinder, and if so how would I check. Again it appears to be in the 5 & 6 cylinder. the engine has been rebuilt about 17,000 miles ago. I have cleaned or replaced just about everything and have also been running injector cleaner through it periodically.

How would I check the injectors and can I pull them without pulling the upper intake

 

hi, to get to the injectors its the intake off first before you can see the fuel rail etc.
i wish i new a way of checking for vacuum leaks there must be a spray available. i have read other posts that refer to using propane but that seems extream to me. bokker.

 

I did check for vacume leaks with both propane and carb cleaner. I did not notice any change in the idle so I will assume that there are no leaks.

Is there any thing else other than the injector which will cause #5 and 6 to be rich.

 

I don't know mych about these engines, but FWIW, a problem with an EGR system can cause rich codes.

 

hi, check the vacuum 90 degree boot that is underneath the intake manifold and the pipe goes to the rocker cover at the pasenger side. these have a habit of disintigrating.
also these engines are critical in regards to spark plugs and more-so plug leads. good luck bokker.