I'm working on an 89 iroc-z that my cousin bought. It had plenty of issues when he bought it. It wouldn't start unless you sprayed starting fluid in the intake but then would stall when it burned up all the fluid. Found out Maf sensor was bad so I replaced it. Now it starts with no problem but runs a little rough. The issue I'm trying to fix now is that if you shut it off and try to restart it it will just crank over but not start unless you let it sit for a while. Computer shows a code 44. O2 sensor lean. I'm thinking a vacuum leak somewhere maybe? Hopefully not a blown head gasket? Any other suggestions?

 

 

Possibly a clogged fuel injector or fuel pump going bad. I would also suspect the O2 as well.
Could be an air leak at the intake manifold, and possibly the throttle body.
Ive even seen some with bad exhaust manifold gaskets, that would run like crap and cut off.