The car:
1992 305 auto tbi firebird

The problems:
1) when driving the shift light will come on in 3rd gear at about 1500 rpm and car slams into overdrive roughly.. feels bogged down and shift light stays on after 1000rpm in overdrive.. my tv cable may be bad, but i dont know if those are symptoms or not. (thats my only guess)

2) my car's usual running temp. is a little under 220. Well it's very hot in LA and it now runs up to 220.. no higher, but when it gets there it runs very rough. staggering to climb rpms. and sometimes even goes dead. i have thought about emptying the antifreeze and using water, because i hear it cools better. there are no leaks, radiator is full and fan blows, thermostat changed, and water pump was replaced not long ago. (have no idea about this one)

I was running very rich and blowing black smoke when i hit the gas, but i changed 02 sensor and it fixed that.. I don't know what to do about these 2 problems though. any help is greatly appreciated.

 

The shift light shouldn't come on at all - that was for manual cars, so that is weird.

You could try a cooler thermostat, or a cooler fan switch, or get an aftermarket adjustable fan switch and adjust it lower so the fans come on earlier.

 

Water is good for cooling but you have to add some anti corrosive additives. also im not sure about this but i think water has a higher boiling point also?

 

a long time ago i put a light bulb in the shift light spot, just to see if it would come on at like 4500 rpm, and it never came on at all until this started happening.

i actually have the double fan setup from a formula 350 and i have one fan on all the time because the relay was bad.

so you guys think switching to water might help too?

 

I think we need to get this sorted out first.

Do you have a 700R4 automatic transmission, or a manual transmission?

 

its a 700r4 and always has been

 

and another odd thing about the already odd shift light thing... if you start the car and dont use a/c the whole ride, the light never comes on and no slamming into overdrive.. BUT if you start the car and use a/c it will happen after driving a very short distance. Then if you turn the a/c off, it STILL does it the rest of the ride. I have put it in neutral and turned the key off, and restarted the car and it will still do it even with no a/c.. I know... its very very strange..

 

TBI car has no computer interaction between coolant temp and mixture or timing changes like a TPI car does. 220 or even 230 is not too hot in these cars, GM designed them to run hot.

So, my guess would be that your guage is off (most stock guages read bad anyways in these cars), and that given the hot air temps of the summer months now you are actually running hotter than the guage reads - running too hot.

I'd get a system flush, install a new rad cap, and get a lower temp thermostat.

If that didn't change anything enough, then I'd get a seperate fan controller if it were me (and that's because 1) I never liked the head mounted fan switch - I never got them to work well at all (even expensive ones), and 2) since there is no computer interaction with regards to coolant temp, there's nothing as far as the ECM is concerned that it will affect. The seperate fan controllers probe the rad, are adjustable to set a lower fan on temp, and I've had mine for 4 years now and it's worked great!

 

ok thank you guys so much for your input! I have new info on problem 2. It happened about 20 min of driving. I came to a stop and I watched the voltage gauge started to drop and the car started running rough and staggering, trying to die. well I cut the a/c off and it recoverd and started running fine. So I think either the air compressor is trying to lock up causing power loss or alternator is bad.. but when air is off this problem doesn't happen at all.

 

edit - sorry wrong thread

 

is the secondary airdam still under the radiator?