I recently changed the coils, intake gaskets, pcv valve, fuel injector o-rings and valve cover gasket on my 2003 Tribute with 160,000 miles. It ran great for a couple of hours then while on the freeway it lost all power and I had to floor it to maintain enough speed just to exit. It starts fine and seems to shift fine but when I drive it the vehicle will only get up to about 30mph and wants to stay under 2200 rpm. The more gas I give it the worse it performs.

I sprayed MAF cleaner around the vacuum lines and gaskets and didn't get a change in idle and no fuel is leaking. It appears to be holding vacuum and the fuel pressure at the test point maintains 65psi. When I idle it up to 2000 rpm (in park) I can feel the motor pulsing a bit. Some have suggested it is a catalytic converter. The EGR valve is also really really hot. I do have exhaust coming out of the tail pipe and no rotten egg smell.

Why am I not getting a trouble code? If it is a catalytic converter, how do I tell which one? They are expensive as heck and I can't throw that much at random part replacement.

As a last resort I was out putting some seafoam in the vacuum lines. When I turned the car off I could hear a 2 second pssssht sound coming from the back of the motor. Is this normal, could it be the vacuum canister making the noise or pressure being released elsewhere?

 

I can give you some good articles on catalytic converter. 160,000 miles on original cat is a lot.!
All Catalytic Converters - How do I know if my catalytic converter is defective?
(video on how to test).

Driving around previously with misfires could help kill a Cat.

 

Thanks, that was it. I unbolted the pipe and found debris from one of the front cats clogging the rearmost cat. I test drove it without the rear half bolted on and I got my power back along with some sharp looks from the neighbors Since I have it mostly apart I was thinking of soaking the rear cat in soapy water like in Scotty Kilmers youtube video, in case there is still dust clogging the rear cat. Any pro's or cons on that?

EDIT: well forget that, the exhaust pipe decided it's not coming off. Vacuumed it all out, bolted it up and the Tribute is back to normal.

 

Just be careful that any debris from the front cat does not get back in to the engine via the EGR valve. This can cause serious damage to your engine!
First sign is a loud rod knock! I was busy today and yesterday. I DJ'd a wedding yesterday and slept in, finished unloading car, watched Nascar, uploaded pics from my camera to send to the bride. Just finished loading some pics on Photobucket.

You may have to gut the front ones! Hope you don't get codes. Some people install O2 simulators for rear ones to trick computer. I am not certain how it's done.

You could by-pass the EGR valve. Basically, you cut off and block off the exhaust pipe that leads up to the EGR valve (from the exhaust down below). With nothing attached to the EGR valve, you put some heater hose (or some other sh.it) and attach it to your intake, before the Mass Air Flow Sensor. (to air intake box, either in to air filter [if cold air filter as per: EGR ByPass.
This way the EGR valve still operates. It now operates with fresh air, not recircled exhaust gases. They go it to quite in depth discussion on: EGR ByPass

At least you probably liked the exhaust note from pipe removal! F the neighbours!

 

Yeah, I am not getting any codes. Thanks for the heads up on the other stuff too. I did enjoy driving the car "un-capped", reminded me of my hot rod days.