I have a 4 cyl A code that sometimes bucks and loses power at around 45- 65 mph. I also get a lot of carbon thru the tailpipe. BUT, the plugs aren't carboned up. It bucks so hard that I can sometimes hear the u-joints banging back and forth like the rear end is going forewards and back. I've done a complete tune up, checked pcv, egr, replaced the computer and checked timing. Also put in a new trans filter and changed the fluid.
Any advice or ideas? Thanks- Laura