Exhaust questions

[Blacktruckdave]

2007 F250 5.4l 140,000 miles. Lots of Hiway towing.
I want to replace the cats first. What choices are best for the Catalytic converters to the 'Y' junction and then would it be wise to keep the stock muffler and or would I be able to upgrade the rear part of the exhaust when I get my money saved. Also should I replace all 4 O2 sensors before anything and OEM or are their just as good cheaper? I know its a lot to ask but I wanna get an idea of what way to go parts/upgrade. Thank you. This is the best forum for Superduty's I have found out there!

 

[blacksnapon]

2007 F250 5.4l 140,000 miles. Lots of Hiway towing.
I want to replace the cats first. What choices are best for the Catalytic converters to the 'Y' junction and then would it be wise to keep the stock muffler and or would I be able to upgrade the rear part of the exhaust when I get my money saved. Also should I replace all 4 O2 sensors before anything and OEM or are their just as good cheaper? I know its a lot to ask but I wanna get an idea of what way to go parts/upgrade. Thank you. This is the best forum for Superduty's I have found out there!

140 thousand miles on OEM, why change?

 

[Blacktruckdave]

thanks Blacksnapon, Truck is very sluggish, I have to put the pedal to the floor to get it to move. I checked fuel pressure at the rail and its fine. changed fuel filter and spark plugs. Also have low exhaust pressure. Can only assume the cats are clogged from towing up n down the east coast over the mountains...Would changing the oxygen sensors have any effect?

 

[Sparky83]

thanks Blacksnapon, Truck is very sluggish, I have to put the pedal to the floor to get it to move. I checked fuel pressure at the rail and its fine. changed fuel filter and spark plugs. Also have low exhaust pressure. Can only assume the cats are clogged from towing up n down the east coast over the mountains...Would changing the oxygen sensors have any effect?

if you have low exhaust pressure your cats are fine.. clogged cats would result in high pressure. but would look into doing those 02 sensors.. the newer 02 sensors have a heated element inside that tends to burn out as they age resulting in false readings. it could be where your problem is. could also be a bad throttle position sensor..

dont know if those 5.7's were cable or FBW.. if FBW could also be the throttle plate motor is on its way out.

 

[blacksnapon]

thanks Blacksnapon, Truck is very sluggish, I have to put the pedal to the floor to get it to move. I checked fuel pressure at the rail and its fine. changed fuel filter and spark plugs. Also have low exhaust pressure. Can only assume the cats are clogged from towing up n down the east coast over the mountains...Would changing the oxygen sensors have any effect?

Nah, meaning, If you're going to change, Go back with OEM. With a scanner, look at 02 sensors both upstream and downstream. If the upstream is varying voltages, they're probably ok. Downstream wont move as much. If the downstream mirrors what the upstream does, cats are bad.