Transmission shifting late, please help!

[zimzam93]

Hello everyone this is my first post and kind of a big problem, of course as im getting ready to do something fun to my car a problem arises. While driving on the high way today i noticed I was having to press the peddle harder and go faster and eventually had to floor it to go up hills. Also my engine was sittting at like 3000 rpms when it normally sits at like 2000. It just sounded like it was working harder than it needed to and like it had no power at all. My and my dad found that my transmission fluid was really low and filled that and it is a little better but there is still like no power and it shifts really late. Im seriously hoping that the cat is clogged becuase this happened on our G6 and it was a clogged cat. I just dont know how a clogged cat would effect the transmission. Ive read that some cars run on a vacuum system that require the car to not have any back pressure or anything. I couldnt find a lot on the subject or what kind of transmission we have in 1999 firebirds, mine is an automatic by the way.

I really hope someone has some insight! I need to figure this out ASAP. Thanks everyone!

[jderry]

I couldnt find a lot on the subject or what kind of transmission we have in 1999 firebirds, mine is an automatic by the way.

It would be a 4l60e. We need more info on when it is shifting late, if it is, or if it just seems low on power. Is the service engine light on?

[zimzam93]

It seemes to shift around 4000 or a tad higher when going from a stand still, and there is a severe lack of power, it seems that when i was on the highway even on a straight away it only wanted to reach about 75 at max and when accelerating from a stop sign it takes a long time to even reach 20

[jderry]

It seemes to shift around 4000 or a tad higher when going from a stand still, and there is a severe lack of power, it seems that when i was on the highway even on a straight away it only wanted to reach about 75 at max and when accelerating from a stop sign it takes a long time to even reach 20

How does the fluid look? Smell?
You may have burnt it up by running it low on fluid for so long.

[zimzam93]

Alright guys the problem has been diagnosed! My cat is bad as i hoped!

So now the plan of action, on my college student budget is to cut it off and put a cutout in its place (just cuz ive always wanted one) and ive heard that when you cut off the cat on a stock exhaust system it can get pretty raspy, but others have said they like the sound. So just in case im going to get a magnaflow muffler and if i dont like the sound im going to put that on there and see if helps the sound. What im looking for is a nice solid rumble when im just driving down the street, nothing over the top just a little noticeable.