I have a 92 firebird with a 3.1 . It ran great, but i had a friend put a new coolant temp. gauge on it(i had a broken hand). when i stopped by he had the intake sitting in the yard and was taking it out from inside the engine block because he said the outer portion of the sensor broke off at the engine block? i got the car back and it misses and lacks power very badly. I have tried everything i could think of and still can not fix the miss.

I have replaced the rotory button, cap, wires plugs. i have narrowed the miss down to the #2 cylinder(took wire off and no change in miss). you can take the plug out and start the car and watch it fire. I have put a new injector on the #2 cylinder(runs off a fuel rail which supplies fuel to all cylinders). I have checked the compression. I have checked the timing. I have even reset the valve lash( in case the lash was set too tight and was preventing the valves from opening all the way). It's a long shot that individual injector isn't getting power, because the car runs on all other cylinders. and before any of you say it, yes, the plug wires are in correct firing order. I appreciate any help, thanks...

 

Hmm, if it started when your friend worked on your car, i'd limit my work to what he touched.

I think you'll notice the expertise on the red-headed stepchild engine of our cars is lacking (check out the V6 forum...).
But in generic terms, have you checked for a vacuum leak at the intake manifold-head mating surface at that cylinder? If it's pulling in a lot of air, it could throw off the AFR enough to make it misfire in that cyl. That would make sense too, since he removed the intake. The timing, valve lash, etc, would be tricky to screw up while playing with the coolant temp sensor.

Try running it, and run some propane over the engine near the intake manifold. (with the plug in that cylinder).