My fiero is running very weird. I almost ran out of fuel one day and after i refueled it it started to sound differnt in the exhaust tone. it is pulsing like it's not timed right but i never touched it. I thought it might be a fuel filter so i replaced it but it still wasn't right. i put in some fuel injector cleaner and ran it for a while but that also didn't help. Today i removed the front three spark plugs and they were coverd in carbon deposits. If i remember right that means it's running rich. I recently replaced my manifolds with ported ones and replaced my O2 sensor. So i have no clue why it's rich. The richness also dosent explain the weird exhaust sound. PLEASE HELP!

First thing I would do is run a fuel pressure check.
It is very common for the fuel pump to fail after running low on fuel. If your pump is fairly old check the pressure.

Could be other things but this would be my first test. The pressure should run 38-43 or so....

Weird exhaust sound --like it ticking, lower tone, plugged up , louder, ?

I will check the pressure soon. The exhaust sounds like when you have a leaking manifold but i already checked for any leaks or cracks and there where none. Very pulsy( i have know clue if that is a real word)

Year , model, engine ? Need some more info --especially on how it sounds and runs...

check for air leaks in you intake you may be suffering from loss of power due to vacuum loss the noise you hear may be that suction.

Something else has come to mind, what kind of 02 sensor did you use, the only ones that have worked right for me are bosch or ac/delco brand..

This is an 88GT has about 60,000 miles. The noise is hard to describe in words. it sounds like a pulsing. Another interesting this is that if i floor it it accelerates to 5700 then sits there for three secounds before rising any higher. this never happend before and is very weird. I have no clue what o2 sensor i used i just bought it from an advanced auto parts. I think it has somthing to do with the fact that i ran very low on fuel and the car has been sitting for awhile since i got in an accedent back in november and only within the last two months have been able to drive it. thanks for the help.

bump

I am now thinking o2 sensor. If i rev it up to 4000 and let it engine break down it stalls. I am so lost.

Have you checked the iac, tps, cts, fuel pressure, map, mat ?

What should i check them for. They are all attached right.

You mentioned your engine is now stalling above, and you where lost as what to do --so I suggested a few things to check or look into..... What is your fuel pressure reading ?