cat. converter???

I assume you have an automatic transmission.

Your engine is connected to the road through a series of shafts and gears and a torque converter. If the engine RPM is changing, but your speed abnormaly remains the same, then either your transmission is improperly shifting gears, or your transmission's shifting bands are slipping (most likely cause), or your torque converter is not transmitting power properly. In either case, it means your automatic transmission needs to be serviced or replaced.

No. If your cat is blocked (and this is very uncommon -- your engine would have to be really screwed up for it to seriously foul your cat), then you would simply lose power and fuel economy.

Try changing gasoline to a different grade and/or brand. Also change your air filter if it's dirty. Then take your warmed-up vehicle on the highway and drive her moderately hard for at least 30 minutes to see if that burns off any sulfur deposits in your cat. If that doesn't stop the smell, then you may have engine problems ranging from a need for a minor tune-up, to more serious issues like a bad fuel injector. It could also signify that your cat is bad, but usually that means you have more serious engine problems (thus causing the bad cat).

- Michael

And since the transmission was serviced recently, my money is on the need to replace it.

That's what happened to me. Well, my muffler clogged from something, but the effect is the same. There was plenty of power up to about 30, then nothing. The motor would not go faster, and the power trailed off quickly.

If the OP is noticing the engine speeds increase but the vehicle speed does not, then major transmission service is in order.

Actually, the OP never said anything about the tranny being mechanically serviced. He simply said that he had the fluid changed.

How does one's muffler get clogged? I can only think of three plausible ways:

1. Getting stuck in deep mud while off-roading.
2. Some animal crawling up inside the tailpipe.
3. Some punk playing a practical joke on you.

If you've ever seen the inside of a muffler, they basically consist of a series of pipes and/or chambers, each typically at least as large as your exhaust pipe (i.e., 2" dia or greater). There is nothing that an engine can spit out that's large enough to clog a muffler (unless it barfs an exhaust valve!). Even a catalytic converter, which contains a honeycomb of channels not much larger than a window screen, is unusual to get clogged with an engine in any reasonable mechanical condition.

- Michael

Alright, what I got was a transmission flush. Yes, I do have an automatic transmission. If it is a transmission problem, why does it not do it all the time. I don't know if I mentioned this in my original post but it only does it sometimes. It was a hot does once and another time it was cool and rainy day so I don't think temperature had anything to do with it. It was done it at low speeds and also at high speeds, or at least while I was trying to get to a high speed. Again it doesn't do this ALL the time. Maybe once a week (considering I drive to school and work everyday). That is why I thought it could be something stopped up. Thanks for your help so far, just if you could answer this last question.

Its and older car with an exhaust system as old and the internal pipe from chamber to chamber has rotted and droped over the intake or output pipe. Had this happen to my work vehicle (ford laser Station Wagon) and boy did it lose power when it fell over the output pipe, hit another bump and away she went. Had the dealer (thankgod I wasnt paying the bills!) check it out and they diagnosed a dodgey valve, so one head rebuild later it still did it.......... next attempt was a new carbie........ still did it............ only when run on dyno and the guy behind heard exhaust note change when power dropped that they thought about the exhaust, changed that and away she went.

weeks

If the engine RPM is mincreasing and the vehical speed is not, it is the transmission. It is slipping under load due to wear and a fluid cahnge just helped it for a little while. It is not the CAT converter. Time to repair or find a replacement for your tranny.

You need to accept your tranny is dying. When they start to slip like your is, it is sometime not consistant and if you baby it at low speed you might nurse it for a while but it at the end of it life because when the right combo of torque fluid temp it slips. I am sorry but their is no magic fix and my advise is to repair or replace it soon because one day it will fail completely and likely at the wrong time and place too.

I've never had a muffler get clogged before, but that doesn't mean it can't happen. And, since it was in my motorhome, we can rule out filling it with mud while offroading.

I suspected the CAT to be the problem, but when I removed it, it was fine. The muffler is the only thing left. I bought a new one and my problem went away. Regardless of what is clogged, the point is that if the exhaust system is plugged, the car will develop what seems to be normal power at low speeds/loads, but then flatten out severely as the speed/load increases.

The muffler is packed with stuff that apparently can break loose and block the exhaust stream. The "stuff" may only be sheet metal, but the muffler can clog, and the CAT can clog too. One would prefer the muffler to clog though, because its replacement cost is much lower.

I'm with SnoMan, the CAT isn't the trouble.

Better get AAmco.

Hi Jeff,

Sorry about the wording in my last post. I wasn't meaning to question whether or not your muffler was clogged; it obviously was. I was just curious how it happened. I did consider rust out. But *usually*, when a muffler/exhaust system that is rusted to the point of internal collapse, it is quite evident by quick external examination because there is plenty of rust-though. But I suppose there are some cheap (or defective) mufflers that can severely rust on the inside without showing any corrosion on the outside.

Too bad you didn't perform an "autopsy" on your last muffler. I would have been curious to see what caused it to clog.

- Michael