Ok, spoke to my mechanic today and he swears by the Autolite plugs he installed and stated he's never had a problem with aftermarket plugs. I've got no better choice but to take his word.

I asked him about checking the converter to see if that's the problem. He said he could cut a section of pipe behind the converter to see into it. He then would put a cut section of pipe back in with clamps to patch it back together. Is there a better way to check the converter? I like my mechanic and I know he's honest, but I would think there is a better way to check the converter?

 

Check out this link...

Catalytic Converter


EXHAUST BACKPRESSURE CHECKS
To diagnose a plugged catalytic converter, you can check intake vacuum or exhaust backpressure. To check intake vacuum, connect a vacuum gauge to a vacuum port on the intake manifold. Start the engine and note the vacuum reading at idle. Then increase engine speed to about 2,500 rpm and hold steady. Normal vacuum at idle for most engines should be 18 to 22 inches Hg. When the engine speed is increased there should be a momentary drop in vacuum before it returns to within a couple of inches of the idle reading. If the vacuum reading is lower than normal and/or continues to drop as the engine runs, it probably indicates a buildup of backpressure in the exhaust. Remember, though, that intake vacuum can also be affected by retarded ignition timing and valve timing. What's more, some engines are much more sensitive to small changes in intake vacuum than others, so checking backpressure rather than intake vacuum may give you a better indication of what's going on.
Checking backpressure requires connecting a pressure gauge to the exhaust system. Use a gauge that reads up to 8 to 10 psi and is calibrated in 1/2 inch increments. Or, use a metric pressure gauge calibrated in kilo-Pascals (kPa). One psi equals 6.895 kPa.

A backpressure gauge can be connected to the exhaust system one of several ways: by removing the oxygen sensor and connecting the gauge to the hole in the exhaust manifold; by removing the air check valve in the air pump or pulse air system and connecting the gauge here; or by drilling a small hole into the head pipe just ahead of the converter to attach the gauge (never drill a hole into the converter itself!). One drawback of drilling a hole is that the hole will have to be plugged by a self-tapping screw, plug or welded shut after you've taken your measurements. Also, drilling is not recommended if the head pipe has a double-wall construction.
Once you've made your connection, start the engine and note the backpressure reading. Depending on the application, the amount of backpressure that's considered "normal" will vary. On some vehicles, backpressure should read near zero at idle, and should not exceed 1.25 psi at 2,500 rpm. Others can handle 0.5 to 1.25 psi at idle, but should have more than 4 psi during a snap acceleration test.
If you find a relatively high backpressure reading (say 8 to 10 or more psi), there's obviously an exhaust restriction that will require further diagnosis. Don't jump to conclusions and assume the converter is plugged because it might be a collapsed pipe or muffler.
One way to rule out the pipes and muffler is to visually inspect the exhaust system for damaged components. Another way is to drill a small hole in the pipe aft of the converter and check backpressure here. If the reading is lower (or is less than about 1 psi), the rest of the system is OK and the converter is what's causing the restriction. Or, disconnect the exhaust pipe aft of the converter. No change in backpressure would indicate a blockage at or ahead of the converter. If backpressure drops back to normal, the problem is not the converter but a collapsed pipe or muffler.
If you suspect the converter is plugged, you can disconnect and remove it. Then hold a shop light by one end of the converter and look in the other end. If you can't see the light shining through the honeycomb, the converter is plugged and needs to be replaced.
You can also recheck backpressure readings with the converter removed. If readings are at or near zero, you've found the problem. But if backpressure is still high, there's an obstruction in the head pipe or manifold. Sometimes a collapsed inner tube inside a double-wall head pipe will create an obstruction that acts just like a plugged converter. Another cause can be a heat riser valve on an older V6 or V8 exhaust manifold stuck in the closed position.

 

Here are additional links...

How can I tell if my catalytic converter is... — Yahoo! Autos

All Catalytic Converters - How do I know if my catalytic converter is defective?

 

Furian: Thanks for the post and link, good reading.

I'm surprised my mechanic isn't thinking in this direction. I still don't like the idea of cutting a section of pipe after the cat to see into it. I'm going to wind up with a pipe that will now have two extra seams and the future potential of leaks. I'm going to suggest to him to just change the converter, period. My fuel milage is getting worse and worse and I'm hearing "growling" noises at times coming from the exhaust.

How much shop time is required to change out the converter? I think I'll be ahead of the game in the long run just to change this damn thing out?

 

They make a what is called a test pipe for your cat which is a piece of pipe that replaces you cat. If u can't find the right one any good muffler shop can make u one. They are legal for test purposes only. Have one installed and take it for a 5 or 10 year test drive. I would never spend money for a junk high priced cat which may fail later anyway. Its my equipment and i will run and equip as I like. I had a brand new 79 cheby with a inline 6 once which had a factory split exhaust that went into one pipe and then one cat and one muffler. I wanted duals and the local muffler would not remove cat for legal reasons so i torched everything off from the two pipes back and drove her down to the muffler shop running straight out of the 2 stubs and had them make me a custom duel exhaust with glass packs. All the oem junk went in somebodys dumpster and i had a very unique sounding truck. Sounded kind of like a cessna 150. I did the same thing with my 05 F250 with the 5.4 but i left the cats on as it has 1 one on each downpipe. If i ever have cat problems it will be time for 2 test pipes. 65 thousand miles on her with no problems so far. Cutting the pipe off to look in the cat is rather stupid and a waste of hard earned money. At that point u are half way to a test pipe anyway so put one in then u can cut the cat open and get a good look. I like to keep everything simple and only have to fix it one time in this lifetime.

 

"Have one installed and take it for a 5 or 10 year test drive"

That's a pretty long test drive.

 

The Autolite plugs will be fine if he installed the proper replacements and gapped them to spec.

 

A qualified mechanic and/or exhaust shop should be able to replace the cat in 30-45 minutes. A "universal" cat will take a little more time... maybe 15 minutes.

Your OEM cat appears to be located after the Y-pipe so it is easy to access. You could make a cut right after the front mounting flange/hanger and make another cut after the O2 sensor bunge. Then, you could weld in a "test pipe" or a "universal" cat. It's an easy install.



Did you contact Magnaflow to determine which "universal" cat is best for your application?

 

Ok, here's where I'm at. I told the mechanic that we should just change this converter because my milage is getting worse and my high rpm power loss isn't going away. I'm also hearing a bit more of the "growling" noise coming from the exhaust at times. My mechanic told me that he could get different converters. He told me one would be about $800 and the other would be $1300, that's for the converter alone.

I'm shocked and pissed that I miss the Ford warranty by 300 lbs.

I started looking online and saw three prospects:

Magnaflow - part number M6660411 - $480.11

Catco - part number cat10924 - $286.99

Eastern - part number EAST30807 - $404.66

Any input on these? I'm looking for direct fit and no problems. They're all listed as direct oe replacements but I'm looking for any information about them. I notice the Catco has an outlet diameter of 3", while the Eastern has an outlet diameter of 2.5". This is what worries me because they both say direct oe replacements.

Any and all input is greatly appreciated.

 

Whats wrong with the 10$ test pipe for installed for 50$ and legal in all 50 states!

 

LOL, yeah no kidding. That is illegal in all 50 states and anyone claiming that should be sued for false advertising.

I would go with the Eastern. I have dealt with all three companies. The Magnaflow is ok, but they use cheap insulmat packing that deteriorates over time, so you will eventually have a repeat failure. The Catco is a cheap design and they have a long standing history of direct fit parts that don't direct fit. Eastern in contrast probably makes the best in the industry. They don't just make their own, they also make Walkers product, and they make the shell themselves, whereas Maramont uses Eastern's shell but puts a cheap catalyst in it. Eastern's product is the best because they have the best catalyst technology, and they voluntarily have a longer warranty. They use the highest quality insulmat, which prevents the catalyst from ever rattling loose.

For the record that Eastern part# 30807 has a 3" outlet. If the seller you are looking at is listing it at 2 1/2", they are wrong, and you should buy the converter from someone who knows something about the product they sell.

 

I was looking on PartsTrain.com and here's what's weird, the Eastern part #30807 is listed as having a 2.5" outlet, the other option on this website is the Catco part #10924, which states a 3" outlet. Not sure if the link will work, but here are the two selected to be compared:
PartsTrain.com - Hard to Find Auto Parts and Truck Parts - Catalytic Converter - For 2003 Ford F-250 Super Duty XLT 8 Cyl 5.4L=

I'm also looking on ecatalyicconverter.com, they have the same two listed above, but have Magnaflow, either M6660411 or M6655322. They also list the Catco having a 3" outlet and the Eastern having a 2.5" outlet. Here is the link for this site as well: Catalytic Converter - Catalytic Convereter | E-Catalytic Converter - Catalytic Converter

The lengths between the Eastern and the Catco vary by a 1/2" also.

I like the Eastern because they're priced in between the Catco and the Magnaflow. The Magnaflow throws me off as well because they have multiple options.

What should the outlet diameter be, 2.5" or 3" for my stock truck? 2003 F-250, 4x4, supercab, 8 ft. bed, 5.4L engine?

It looks like I can get one of these for about 1/2 the price of what my mechanic wants to charge, just for the converter. I don't think he'll mind installing anything that I bring him, but I just need to make sure I order the right one, otherwise it becomes a major hassle.

Any one else got experiences with any of these?

 

I would be hesitant to buy from partstrain and here is why. Even though the product has a warranty, in the event you ever had a problem, good luck getting it resolved. Partstrain is an automated parts seller. People do not actually sell your product. That is why their listing is wrong. They don't know the product they sell. Their tech support department is probably overseas and they sell cheap because they have very little overhead because they have done away with the customer service. Autoanything and many other websites will have the same listings and prices because they are the exact same thing. They are all owned by a larger company that runs and maintains these various websites.

Catalytic converters are highly technical products and require that the people who sell them know something about them. Otherwise if you have a warranty problem, or a fit problem, or even just a question that is not explained in the listing, you are left on your own.

But to answer your question about what to buy, the eastern part number as I explained is the right one, and does in fact have a 3" outlet size. Thats the only way it is made. Catco is known for fit related problems, which explains the difference in length from the Eastern part. But you just can't go wrong with the Eastern.

 

ok i just read this thread and i have the little magnflow universal cat on my truck and if you tow allot it says it can clog quicker? is this why everytime i tow my backhoe it smells like a brand new cat was just installed? other than that i have no other problems whatsoever.

 

I agree about buying from online and that's why I'm frustrated. Both of those links list the Eastern as having a 2.5" outlet. Like you said, they're probably all the same place in the end? But they both list the 2.5" outlet, and that worries me. Does anyone else have experience with this Eastern part number, EAST30807? I still can't understand why my mecahnic is telling me $800 for a cheap one and $1300 for a good one. I'm missing something because I know parts get marked up a bit, but something doesn't sound right?