Okay, just as the title says, my car is running terrible, and I have no idea whats wrong with it. It's the car in my sig in case your wondering and the parts I have already replaced are as follows. Opti, plug wires, plugs, coil, icm, fuel filter. I also checked the fuel pressure and it has 42psi. When it first started acting up it would run fine up to about 4500 rpm, and it then it would start popping and pouring black smoke. But now it skips sometimes, and it has lost power. It also sounds strange when it's reving up. It sounds like it is sucking massive amounts of air. Anyway, it isn't throwing any codes either. So I need help. I haven't been able to drive my car in well over a month.

 

And no one else has any idea. Great, so, anybody want to buy a Firehawk?

 

I wish I had an answer for you
I'm sure someone here will pipe up within the next day or so.
You might end up taking it to a shop for a diag if no one knows.
Or even hooking up a scan tool yourself

Black smoke usually means burning fuel or a cylinder not burning properly.
I'm trying to think what kind of leak would cause additional fuel to dump at higher RPM with a stock FPR.
I'm starting to think it may be a sensor (O2 or TPS) and not a leak at all.

Do you know where the sucking sound is? (or did you mean the sound at the TB?)

This all started out of the blue?
Not after an install or repair? (specifically thinking fried PCM or bad injector)
Anything else seem strange?
Did any of the old plugs look fouled?
If the car is running in limp mode (fried PCM) or running on fewer than 8 cyls, it can make a poping sound.

It looks like you swapped out a lot of parts in troubleshooting.
You pretty much ruled out ignition.

 

maybe a maf sensor? fuel pump?

 

Maybe get your computer tuned again

 

have you done any mods lately? and did you check your o2 sensors, and the pluf for the maf? my car ran horrible until i noticed one of the 3 pins in the connection for the maf was bent, so i unbent it and it worked alot better and no backfiring, same with the o2 sensors

 

I think that would be the best things to start with.
Either of those could cause air/fuel problems.

 

It just started doing it out of the blue and I haven't done anything to it lately. The plugs were worn but not fouled. Like I said above, when it was popping and pouring smoke, it ran perfect until 4500 rpm, and now it runs terrible all the time.

 

I had no idea o2 sensors would cause it to run bad but I will try that next.

 

how did you check the fuel pressure? the pressure seems a little high... you might need to replace the fpr.

 

THat's good fuel pressure.

 

Not if he did it with the hose on and engine rinning. It would be way too high!! cause it to run rich. You need to remove the hose if the engine is running or check it the key on and engine not running.

http://shbox.com/1/4th_gen_tech2.html#fuel_gauge

 

that fuel pressure is fine. wanna know what bad fp is? try 60 at idle with a stock pump and 70 psi wot LOL. try the o2s, I had one that was faulty but didnt cause the engine light to come on and it was running the same way your car was. also if the cat has never been replaced there is a chance of it clogging. but i would lean towards the o2's first

 

Ill tell you goo FP. good FP is 20psi at prime up, and 35psi wot.... that was hella fun.

 

OUCH Yea i think i would rather have my rich condition than your lean one.........