Ok so I have a 1990 Firebird Formula with the 5.7 motor. It was running great until I want to say mid January. I went to a shop that my family has gone to for years, and they said one of my fuel injectors went bad, so I swapped them all out. It didn't seem to get any better, honestly it seemed to get worse. So I brought it back and then it ended up being another thing on the intake manifold(I think. Sorry I have no idea what that part actually was.) anyway, I got that replaced and it seemed to run just a little better but now it randomly stalls(very randomly not too often) idles weird and just isn't running good anymore. If someone can give me some advice or can tell me what this possibly is? I would really appreciate it. If you need anymore details that I may have left out that could help ask away. Thanks in advance.

 

Random stalling and bad idling could be a sign of a vacuum leak somewhere.

 

Start by pulling the engine error codes

https://www.thirdgen.org/forums/tech...s-dumbies.html

without those anything else is guesswork

You might also confirm your fuel pressure is correct

 

Disable the egr valve, the control solenoid might be letting vacuum leak by at idle/low engine speeds. Drive it like that for a few days to see if it acts up.

 

...

 

Check for codes, if any.
Look for vacuum leaks.
Check the fuel pressure. Check with key on, engine off, and then check with engine running. Check how it responds when you move the throttle. Fuel pressure should maintain a constant differential versus manifold pressure. That's the job of the fuel pressure regulator.
While you're at it, if possible try sucking on the vacuum hose that leads to the FPR. If it lets fuel be sucked out of it, it's leaking.
Check fuel pressure after the key is turned back off. It shouldn't lose more than maybe 3psi in 20 minutes. If it's dropping much faster than that, you have a leak somewhere, possibly a leaking injector or a bad O-ring.

With the work you had done, both vacuum and fuel issues could have been accidentally created, even if they weren't part of the original problem.

Under what conditions does it stall? Idling, or at speed? Does the rough running and stall seem to happen when cold, hot, or any sort of pattern that you can tell? Does it restart easily?

 

It stalls usually at idle. Um I am not sure if it stall when cold or hot. It varies and its so rare when it stalls that I'm not sure but it's almost always runing rough on idle. It isn't extremely rough but it never stays at a set rpm. And when it does stall it usually is easy to restart. I just have to put it back in park and it'll restart. But a lot of times lately starting it cold more often then restarting but sometimes restarting, it'll take a bit to start and sometimes I have to give it a little gas to actually get it started.

 

To be honest I have no idea when I last changed that.

 

What and where is the egr valve and control solenoid?

 

How do I check the fuel pressure? And thanks for the link to the code stuff.

 

Ok got the codes read, they are 12 and 32. Any ideas on how to fix?

 

Light should have flashed 12 before and after any other codes
See
http://www.corvettephotographs.com/c4vettes/codes.htm

Have to work out what part of the EGR system is faulty 1st

Do the tests in link below
http://www.chevythunder.com/egr_code_32.htm

 

I was told I should just delete the EGR/A.I.R. System. Should I? Could that fix some of my problems?

 

You haven't identified WHAT actually is the problem yet

AIR you can remove with no problems.
Removing EGR may give a permanent SES light and you will need a custom chip with EGR delete on it to make it go away

 

Ok so I see there is supposed to be a vacuum line on the egr valve. I can't seem to find any reference pictures of where or what this all is supposed to look like. Do you have any reference pics of all of this?

 

Ok on the second link you sent me it says check the vacuum lines. Idk if I'm looking at the right thing, but isn't this the egr valve and shouldn't there be a vacuum line connected to it?