Hey guy`s and girl`s have a strange problem wondering how to fix it? I have a 97 cherokee 4.0 6cyl. auto that has been giving me trans. problems. Shifting oddly or hesitating and when you hit the gas pedal hard it feels like it neutralizes ?? I changed everything , (tps,pcm, shift solenoids and o.d. fluid and filter etc., ) I checked every connection the n.s.s. has been removed and cleaned and all linkage checked.. I ended up replacing the entire unit (transmission and converter) with a known good one from a wreck (97 cherokee sport)I had purchased awhile back.. ,still same exact symptons I brought the jeep to a transmission guy who drove it around with me in the car hooked up to a scanner tool , he felt it was working properly and asked me to leave it overnight.. The next afternoon he called and said he went all over the car and felt it was engine problem and not the trans and he felt the cat. converter was clogged? So I want to remove it and replace it with a new one but really need to know if that is the problem first.. I know it is frowned upon but I do have a hollowed out factory cat that I could use for test purposes, my question is will that throw a code right away or is their another way of checking it out?? I hate to think it was that after swapping a trans that probally did not need to be replaced if that is the case with the cat ,but would be happy if it repairs the truck..Can not really drive it like this it is like it loses power when you hit the gas pedal.?? Oh the truck has 150,000 on it and did a compression check low cyl. is 143 high is 146 from cy.l 1-6 motor run`s very well. Any thought`s comments would be appreciated.. Oh the trans shop did not charge me for any of the diagnostic work which I found hard to believe but it just goes to show you their are still good people out their.. Shop is in w.babylon, n.y. Thanks ,Bill

 

couple ways to check your cat, one exhaust usually smells like rotten eggs, another run it when its dark before shutting off put in park and look at the converter if its glowing red then its bad. next option gut it, which i dont suggest and see if it still gives you the same problems

 

ok I could not drive the jeep the way it was so, took out the sawzall and cut the cat out replaced it with the hollowed out cat put the 02 sensor in it put muffler/tailpipe back on took her for a ride and it run`s like a brand new car!! It still has not thrown a code but All I keep hearing is that you should not run a hollowed out cat ??. Is it for pollution purpose their is really not that much difference in noise the muffuler is new it is a walker, the cat I took off was a high flow from the muffler shop piece of junk, only about 2 years old never again, but it was shorter than original so that allowed me to use the factory cat that was hollowed out , was in my spare parts..Anyway the trans shifting problem is gone and it really runs well the exhaust is just tacked in the car so if somebody can please tell me why the hollowed cats are frowned upon please let me know (read that while searching) , I am all for keeping the earth green, and would also like to know if their is a mechanical reason.. ?? Also really like to thank the transmission shop for their honesty if you ever need a honest reilable shop in Long Island go and see Neil at Long Island Transmission in West Babylon , New York.. He did not even charge me for the diagnostic..

 

If you have access to a vacuum gauge, here's another way.

CRUISER’S VACUUM TEST FOR EXHAUST RESTRICTION

Your vacuum gauge should come with an instruction booklet outlining the procedure. Hook the vacuum gauge up to a source on the intake manifold. Start the engine and note the vacuum reading. Usually 17 to 21 inches of vacuum. Throttle the engine up to 2,000 to 2,500 RPM for 20 seconds or so and the vacuum reading should stabilize to the same reading you got at idle. Let the throttle snap shut. The vacuum reading should shoot up about 5 inches of vacuum higher for a second and then come quickly down to the original reading. If the vacuum reading stays high and comes down slowly with jerky needle movements, you have an exhaust restriction.

 

Thanks, yeah my buddy just told me about.. I do have a gauge and will remember that for the next sign of trouble? Hopefully I will be ok I am heading up to advance auto to pick up a direct fit walker cat., I do appreciate the advice Thanks again, Bill

 

Vacuum gauge is an incredibly simple and effective diagnostic tool.

http://www.classictruckshop.com/club...ts/vac/uum.htm

 

If you have an O2 sensor after the catalytic converter it can cause problems when you remove the converter because it will get the wrong readings. There are ways to make your car run VERY clean without using a cat, but most people don't keep up on maintenance so a cat is needed to keep the exhaust clean.

 

For future reference easy fast way to check for a clogged cat remove an O2 before the cat and take a quick ride. That should help diagnose without removing it.

 

I've heard of that. Just always had a vacuum gauge handy.

 

I need to get one. How much do they run?

 

Under $20.

 

Would an in dash type vacuum gauge work the same way?

 

Absolutely, and it's a great tool for maximizing your MPGs.

http://www.ehow.com/how_8098066_driv...-gasoline.html