well ive got a 99 SLE with a fairly new transmission in it from a le sabre, everything runs perfectly on it but it is very slow at least to me.I got the car about 2 years ago and the dealership gave it a tune up with AC delco wires and autolite copper cores. Ive kept up with fluid changes and i have a gutted air box with a 9 inch k&n filter, i dont know if its just my driving but its SLOW.It hesitates all the time, i have barley any power in overdrive, and acceleration is not impressive. I also scanned it the other day because my check engine light came on, it came up as an emission sensor, i dont know if its serious because the light only comes on every now and then.Does anybody have an suggestions?

Is your Bonnie getting slower as it warms up?

well it seems to run better when its still kind of cold around 180 degrees, but it does seem to have better acceleration when its cold.

hmmm, depending on what your code is (could you post it?), I'd say you MIGHT have a bad catalytic converter, but there'* no way to know without knowing the exact code you have...

When you go out to your car (when it'* COLD, don't burn yourself ) try to shake the catalytic converter (if you don't know where it is, it'* a bulge in the exhaust system almost right under where your dashboard would be...), if you hear a rattling, like rocks in a rock tumbler kinda, then its a safe bet that your cat is bad...

(btw, I noticed you already told us your year and trim level in this post, but could you put that info in your signature? It will help us diagnose future issues quicker )

im not 100% sure on this but i think the code was P0454, ill check the CAT tomorrow.

SLE likely had a 2.97 gear, but the lesabre trans you put in may be 2.84 geared, with a different torque converter, may make the car feel slower. Just an Idea.

Wrong gearing would also screw up the shift points.

We had a member recently that got the wrong gear ratio, and the trans shop had to bite it and replace it at their expense when he proved it.

http://www.bonnevilleclub.com/forum/...ic.php?t=90922

Follow the advice in that topic to identify what your car came with, and what it currently has in it.

well the transmission shop realized that it wasnt the right ratio so we had to take it to a dealership and have them program the le sabres VIN in so the shift points would be right.Does anybody know what the stall speed of these torque converters are?

You got hosed. And you'll still have the wrong ratio, less power off the line, and never be happy.

Take it back to the trans shop and DEMAND they install the right RATIO to match your RPO codes and programming. You have no idea how badly you're getting raped here.

im actualy very satisfied with the transmission its one of the smoothest ive ever driven and ive had no problems with it at all. And i dont notice that big of a difference in power in changing from the original tranny. I think that its problem is the engine, the person that had it before drove the crap out of it, enough to where the 4th gear clutch hub completely wore down which is why i had to change it.Maybe the engine just has a lot of wear and tear on it.