Javelin3o4

Im about to take this bird out back and put it out of its misery.

Here is the situation, Ive posted before this issue but it seems that everytime I think im done with repairing this car more issues arise.

Well one day the car just idled really rough and the car stalled, it sounded like it was missing. So it seems that when i first start the car it will idle fine, when it gets up to operating temp the needle on the tach will wiggle between the 500 and 600 rpm line. it sounds like the engine speeds up, then slows down again like its missing. I checked around the vacuum lines but it didnt seem like there was any leak I even disconnected and plugged the line going to the vacuum tank and plugged just incase the tank was cracked. When i unplugged my IAC connector it didnt seem like there was any change in idle/RPM, also when i first disconnected the vacuum tank line at the check valve it didnt seem like there was a change in idle/RPM there either I dont think its a fuel issue because i hooked up my pressure gauge and drove around with and the PSI held and did not fluctuate and when it seemed like the RPM's were jumping around at idle the gauge held steady. Its not throwing any codes either. I listed to each injector and all of them were clicking to show they were atleast pulsing. I've replaced the following parts.

1990 Firebird V6 3.1

Spark Plugs
Cap
Rotor
Ignition Module
Check Valve
IAC Valve
TPS
Fuel Filter
Air Filter
PCV Valve

So if anyone has any suggestions please let me know. Otherwise if i can't get this thing fixed im gonna have it crushed.

96SS1901

you may want to simply clean the throttle body, i have had a few come through the shop that had gunked up thottle bodies

Javelin3o4

thanx for the reply, didnt think i was ever gonna get one...but i sprayed it with throttle ody cleaner and wiped as much as i could with a rag but still having the issue.

oil pan 4

MAF fhey can cause problems with out throwing codes.
Unhook your knock sensor.
Have it scaned with a reader and you can find weird readings from faulty sensors.
Get a guage and see of you have a vaccume leak.
Make sure you fuel psi is good, look for bad pump or your lines could be falling apart on the inside.
Drain your gas tank, it could be sh!ted up with ****.
Unhook each injector 1 at a time and run it, you unhook each one and test them. If you pull one and it runs real bad then that one is good if you un hook one and it doesn't change at all or very little you found a bad one.

Javelin3o4

i checked autozones and partsamerica and they dont list a MAF sensor for a 90 Firebird v6 MPFI engine. As fas as checking for a vacuum leak is there anywhere specific im supposed to hook the pump to?