I want you to check something. Everything you have described sounds like the catylatic converter is plugged. I will kill engine power. Check for back pressure from the exhaust. Listen for whisteling or ratteling from the converter area. Also, if you can, disconnect it to see if it runs any better.
I can't be sure, but now that you described the turbo like sound, that is what I'm thinking. I can't think of anything in the trans that would stop you at 50mph. Especially if it is shifting good, not slipping.
Let me know.
Wednesday, April 8th, 2009 AT 1:31 PM