Now I have stiff brakes, rough idle, and my trans doesn't want to shift. I'm thinking its a bad vacuum leak but any ideas?

Need WAY more info here, but I will say that the 700R4 doesn't depend on a vacuum modulator for shifting. I'd also guess a vacuum leak, on the order of possibly a disconnected brake booster hose.

I'm having a rough idle and the motor slowly revs up. Im thinking its the tps. Does the tps tell the transmission when to shift?

LOL Maverick I was thinking the same thing (disconnected brake booster hose).

SpeedoDeedo what did you mean by the title, "after fuel injection install"? What did you install (and why)? Is your EGR stuck open? Catalytic convertor clogged? Firing order wrong? Check the transmission dipstick, if the fluid is dark brown/black and smells burnt then your transmission is cooked (hopefully not). A trans that doesn't shift could also mean the TV cable (throttle valve, attaches to the throttle linkage) is disconnected/snapped or really misadjusted.

... Because of the whole "stiff brakes" thing, right?

Anyways, our transmissions are old-school. There's really only 2 parts that tell the trans when to shift, the throttle valve (TV) cable attached to the throttle lever (with the green cap that attaches to the lever), and the governor that is in the back of the transmission's main case (excluding the manual shift valve attached to the shifter to place the trans in either a drive gear or neutral). If it's not shifting, you have other problems possibly completely independent of the fact that the engine isn't running. The TPS has nothing to do with the operation of the 700R4 except for the fact that it tells the ECM the throttle position so the ECM knows whether to lock the torque converter or not.

As for the rest, we need to know the year of the car so we know where to start with this, what work was just performed and why, etc...

1991 camaro rs 3.1. Brake booster hose is connected. The motor would run until warm then die. There was one bad fuel injector so I replaced them all which now the car runs.. at idle RPMS slowly build up and the brake pedal doesn't go all the way down when i'm stopping. It also sounds like the car has a big cam in it.

Is the MAP sensor plugged in? Both electrically and mechanically (hose to plenum)?

Sounds like it may be out of time or a vacuum leak, or the the MAP sensor is faulty, not plugged in or not connected.

Do you have any way of connecting a scanner to the ALDL port? Possibly an ALDL cable and a program like Tuner Pro RT, to see what the ECM is seeing?

Barring a tuning program/scanner, you can use a voltmeter to look at specific inputs to the ECM, like the MAP sensor that should be around 5V at key on engine off, and around 1.5V or so while running at idle. TPS, should be at around .65V with the throttle closed and go up as the throttle opens....

when I installed my throttle body I just connected all the cables to it. Are they supposed to be marked or anything?

I had the same problem with my 92 RS. Turned out the rubber hose connecting the steel brake line to the caliber was deterorating and clogging causing a vacuum problem. I'm not saying you have the exactly the same problem, but I would definately check for a vacuum problem...

Check the vacuum diagram under the hood, if it is still there, for where the vacuum lines connect to.

Just a shot in the dark here but when you replaced the fuel injectors, did you use new O-rings? Did you lube them before installing the injectors? Using the old rings again or not properly lubing them can cause huge vac leaks that will make you rip your hair out trying to find. Also what is the condition of your catalytic converter? If it's busted up inside, the car won't idle or idle very poorly. Also a collapsed diaphragm in the brake booster will also cause the symptoms you speak of. The cables on the throttle body should have colored connectors on them to tell them apart. The TV cable should have a green connector on it and the throttle cable is black. At least on my car :P