I've got a 1990 3.1 firebird, my problem first started about a year ago. It started to act pretty weird every time it rained. It would start up just fine and I would always get about a mile down the road and it would start to choke out and hesitate really bad, I would take it home, let it dry out for about a day and then it ran perfectly fine as if nothing ever happens. Just recently, while driving it, I tried to get down on it and when it hit about 3500 or 4000 rpm it died. I pulled over and it started right back up and drove it home with no problems. The next day I got in it and it was idling really rough and would die when revved up to about 4000 rpm again. It also seemed as if a cylinder was out. So i replaced the wires, fuel filter, and checked the plugs(they're not even a year old) and it was still idling rough and shutting down at higher rpm's. Then I thought that maybe it was the EGR valve, it did look pretty bad, so i replaced it with a brand new one... still no change. I finally gave in and took it to a shop to get it diagnosed, he told me that my distributor and the ignition coil was bad, I then replaced both of these and STILL have the same problem, and now it's getting worse and wont even stay running for more than 2 seconds. I finally got a hold of a friend that's a GM mechanic and he's taken a look at it and can't figure it out either, he did find out that all 3 cylinders on one side are out, but they all do get spark. We've thought that maybe it could either be the computer has gone bad, bad injectors, or maybe there's a wire around somewhere that's touching something or shorting out...... anyone have any ideas???

 

its probably going to be your fuel pump since it dies i think the fuel pump isn't feeding enough gas to the injectors that's why it dies on you. or maybe clogged injectors put some Lucas fuel additive if your lucky it will eliminate the problem if not its going to be the fuel pump

 

I did ask both mechanics if it could be the fuel pump and both of them said that it seemed fine, but no one has ever checked the pressure or whatever to really know. It does turn on when I first turn the key and I can here it going.
I've heard that it's a real pain to replace the fuel pump.

 

yes it is a pain...because you gotta drop the whole gas tank that's the only way to get to it. the actual pump itself is 200 at the most but if you don't do it yourself labor will be a lot. or check your tps and your IAC valve ,but since it dies at idle and high rpms it seems like it is the fuel pump not giving enough pressure but it wont hurt for you to check your tps and IAC valve.

 

Well...What else could it possibly be?

 

I seriously doubt the fuel pump is bad, but I haven't hooked up a pressure gauge to see if I have 43 PSI not running with no pressure drop... (hint hint)
If you say that one full bank of injectors is out, I would try to find out why. That's where the problem is. I doubt all 3 injectors are bad, so the problem lies in either the driver module in the ECM or the wiring between the ECM and the injectors. Also, there is a fuse in the fuse panel for each bank of injectors. One is labeled "F/P INJ 1" and the other is "INJ 2". If one of these is blown, I would try to find out why before I tried to replace it.

 

Not entirely true. If you're brave you can make an access panel through the floor of the hatch area.

 

the whole acting up while its raining out makes me think the distributor cap is cracked/ and or loose.

 

There's that and the fact that wiring tends to do funny things when wet. Couple of years ago, when my dad had just bought his 00 Grand Prix, the speedometer would fail to work when it had been raining out. Fix cost $400. Even sooner than that, my mom's 93 Plymouth has been having troubles with the ACC circuit for some time. Mostly out, the circuit would only work when it was cold out and wet (during the winter, thankfully, the only time the defroster, same circuit, would work). Turned out to be a bad connector that I ended up replacing with a section of wire. Just some food for thought.

Seems to me you have a watery wiring problem somewhere that has finally killed a full bank of your injectors, especially since you have replaced just about the entire ignition system. You could also have bad fuel pump wiring, but the injectors are easier to check, and I would start with those first.

 

Injectors can be a common problem on these cars. It is also possible you have a line blockage.