5.4 gave it's "balls" away...

[johnboneske]

I have a 2003 Expy EB. It has a 5.4 in it, just turned 192k. For the last month or so, it feels like it has no power. None! When it is coming up to temp it seems better, but when fully warm, the engine feels flat.

I replaced all the coil packs and installed iridium Bosch plugs in it, cleaned the throttle body, cleaned the MAF sensor (with same cleaner) too. Air filter is clean. No check engine light, no flashing ses light nothing...

The drivers side front CAT honeycomb inside is loose. It rattles around unless under load, then it stops. I looked and it has 4 cats on it. Is it a clogged exhaust? I don't want to get rid of it. I love the truck, it just runs like poo-poo!!

For those who have done it, can I replace the CATS with aftermarket ones, and only get 2 of them. I notice the back 2 CATS, are after all O2 sensors, or are they resonators? I do have an aftermarket dynomax muffler on it.

Please help! I live in Columbus Ohio if anyone is near by...?

 

[johnboneske]

From idle to 2500rpm it at least has some throttle response(not much), above 2500 to 3000 very little, and above 3000 it has none!! It fights staying up to speed(approx 70 to 72mph) on highway with slight incline (less than 7°), and usually has to downshift out of overdrive.

I don't want to throw a bunch of money at it. The only thing I can come up with is CATS and new 02 sensors front and rear. But, that's $400 plus install. So, want to make sure I am right and not pis off the wife before doing it.

 

[johnboneske]

Come to think of it... it has pushed off the EGR hoses from the exhaust manifold to the EGR sensor twice now... I have felt it when it is running and there is 15 to 20 psi pushing out of the lines. That's a tell tale sign of a clogged CAT right? Should I replace the one side or do both sides? ALOT of money to do it all...damn!!

 

[Hayes Riviere]

There are ways to clean out your catalytic converters, you can find them on Youtube or google. You can also buy second-hand cats on ebay, craigslist, etc. You can also fit aftermarket catalytic converters onto the truck, you don't have to stick to Ford's. It could also be the fuel injectors. Have you checked the F-150 forum? It sounds like this truck driver with the same engine and a similar model year has the same issue.
https://www.ford-trucks.com/forums/872102-5-4l-stumbling-and-loss-of-power-need-help.html

Edit: I forgot to mention that the truck driver had clogged catalytic converters as well.

 

[Allen Miller]

That sounds an awful lot like clogged cats. RockAuto has good prices for aftermarket catalytic converters, but the odds of finding a used one for sale are pretty low, since it's illegal to sell used catalytic converters.

You might need to change your fuel filter too, but that's just a general maintenance thing.

 

[johnboneske]

It was the cat... I had one side replaced today (drivers side cats). $600 plus tax. Ouch!! It has never run this good since I owned it. Or at least think it hasn't? I hated spending the money. I live in Columbus Ohio and no one I could find would even consider doing both sides with a single cat on each side... I wanted someone to make a custom system. Was told no by all of the shops. We don't have CARB testing here either.

But, it is done. I have new Iridium Bosch plugs in it and coil packs too. Cleaned the throttle body and MAF, runs smooth!! Thanks for your help!

 

[Hawaiianbasshead]

Can we use spark plug extensions to move the o2 sensor out so it doesn't throw codes? I did that on my titan when I got long tube headers. My 07 has 120,000 and runs like shit and the exhaust mani gaskets are leaking. I know guys here will straight pipe bypass the cats just want it to not throw more codes or go into limp mode. Thanks for any insight!