During the past month or so, my brother fixed the following: exhaust leak, vacuum leak, and bad idle air control motor. These made the car run a little better but it still had the following problems for three months:
1) Wouldn't upshift normally
2) Wouldn't downshift at all
3) Cruise control did not operate
4) Car had only slightly more power than stock
5) Ran very rough.

Last night he found the problem causing everything. The shop that did my upgrades had hooked up the throttle cable incorrectly. There are two places it can hook to on the throttle body, and they had it on the wrong one.

This fixed all of the problems, and now the car has so much power it shreds the tires, even when starting from a roll.

Also, the shop forgot to tighten the bolts for the muffler, and they put my gears in incorrectly, causing them to need replacing, which was done by another shop. Passenger side lifters still make tons of noise.

I kept telling the shop it didn't run right, but they said it was OK.
Sometimes the customer is right.

 

That sucks. Glad you got it fixed though! There are a lot of shops out there that don't know their buttholes from exhaust pipes.

 

most shops actually do know whats going on, they just dont want to admit it, because they dont want to fix it. some people have no morals i swearta god.