Ok this problem just happened to me a couple days ago. It was a pretty hot day so i decided to turn on the A/C and it ran fine for like 20 mins then all of a sudden the car bucks in first and second gear. I did clean my engine bay 2 days prior to that but it ran fine after the clean). Prior to this the car was running perfectly. i read previous posts on bucking/hesitaion but mine seems to be really bad. After fiddling around with it yesterday and today i did the following

1. Cleaned the IAC
2. Did the Map Whack
3. Cleaned the throttle body.
3. checked for vaccum leaks
3. Adjusted the throttle cable( 1/4 play)

Here are some of the symptons

1. Revving in neutral at around 1500 it feels like there is no gas going to the engine
2. The car will stall every so often(when i push in the clutch coming to a stop)
3. Going on the highway at around 3000RPM i push the gas to accelerate it takes like 2 seconds for it to respond.
4. in first when i get going it bucks like crazy and the only way to get rid of the buck is to push the clutch in and rev it high and ride the clutch.
5. Hesitates in every gear when i want to accelerate(like 2 second delay)


oh yea it also threw a code ( either running too rich or running too lean) its prob the running too rich one because i can see black smoke coming out of my tail pipes.

Anyone have any suggestions?