Ok fellas, ya'll have helped me out before. I have a '97 F250 4X4, 5.4. I also have a 5th wheel camper that i have now pulled twice with it. I know the gas mileage is not going to be great, but I didn't think it would be quiet as bad. I have done a tune up, had the egr replaced, and ports cleaned. Cleaned maf, also replaced 2 cops. The truck seems to run good, but seems like it's missing something especially with a load behind it. It also has a strong odor, especially when at idle. This was my first big road trip with the camper, and it was very noticable that when you were on much any of an incline that the thing just didn't seem to have the power it should. I would lose anywhere from 5 to 15 mph. Maybe ok, but just don't seem right. I have questioned the cats before, and was wondering if this could be the problem? I'm also thinking about going with duals. Will this help me any at all, or am I just spinning my wheels here? I would also like to know what the symptoms of a stopped up cat are and what problems can it cause? Just curious there. Should have mentioned that it has 155k on it. Thanks.

Had this one posted in engines, but thought I might get some good responses here as well.

 

A bad cat should throw a code. But it could be partially clogged and not throwing a code.

A backpressure test is easy enough for any exhaust shop to perform, takes about 15 minutes and shoudn't cost much at all.

If you are feeling a miss, it could be the plugs...how old are they?

 

The plugs only have ablut 2500 miles on them. All of the work listed in the original post has been done in the last 3000 miles. There seems that there may be a slight miss when you first crank the truck and it is sitting at idle. when you drop it in gear it goes away. It also seemed to pick up a slight miss at times when climbing a hill with the camper, but I'm hesitant to say that was for certain. It kind of felt like it was in a strain on much any kind of a greade. If my figures are right, the mpg was maybe 7.5. The last time I checked it around here it had dropped to around 12.6, which may not be bad, but it was up around 13.5 after the tune up.

 

What kind of oder?

 

Kind of a burnt fume smell coming straight out the exhaust. Most any time I have ever smelt it on this or any other vechicle I've been led to believe that it was the cat. It has not thrown any kind of a code as of lately. The two that it has thrown in the past were for the egr flow and a bad cop.

 

Cats have a distinctive odor, if you've smelled it before then you likely know what it is.

The odor after a long uphill run is normal, your cats are getting hot. But the odor at idle is odd.

You did the other things I'd recommend, like cleaning your EGR ports. Since you haven't had your cats checked, and it's a cheap thing to check, you may want to try that.

 

I haven't had them checked, but did talk to a guy at a local shop(turned out to be somebody I know) and he thinks it is probably the cats. Turns out that there are 4 of them on there. A small one first that feeds in to a large one on each side. He says he can take it all out and replace them with a pair of Magna Flo High Flo cats. It will run me about $350 parts and labor. I'm also considering duals a little further down the road, but can't quiet swing it all right now.

 

A backpressure test will tell you for sure.

Magnaflow high-flows should be under $100 each (more like $60 or $70), so the rest he's charging is for labor. Not saying it's good or bad, just letting you know.

If you are getting duals or an upgraded exhaust, just do it all at once, you'll likely save a bit on labor versus doing it a little here, a little there.

I'd check your local laws to make sure you don't have a visual inspection before tossing the pre-cats (the front ones). If you do have a visual, jsut gut them out or run a pipe thru them. If you don't have a visual test, then you have nothing to worry about.

 

You haven't said the size or weight of your fifth-wheel. It may be aload for a 5.4 F250. Losing speed on incline is common.

 

I think the fifth-wheel is around 5500. I probably wouldn't be to worried about the drop in speed if it didn't seem drastic, but it would be 10 to 15mph or more at times. Just seemed like alot.

Here's the latest. Jbrew, you asked about the odor and this should answer that question. When I was getting ready to leave work today, I cranked the truck and let it idle. When the engine was cold it wasn't too bad, but as the truck come up to running temp, it absolutley stank, for lack of a better description. Not a real gassy smell, just a bad smell. A friend of mine was there and smelled it and said it was the same smell he had before replacing his cat. Jordan not Mike, on the inspection, here in LA(lower Alabama that is ) we don't have one, so no problem there. Thanks though.