Car Won't Hold Idle (loses top end too)

[MikeV6]

Sometimes when I start my car, it fires/cathces, then just sputters right back out. It is like the car won't hold idle. If I hold down the gas to give it some RPM's, its fine. Once I put it into first gear and drive a bit, or rev it to like 5000rpm, the problem is solved and it will hold RPM's again when I press the clutch in.

This will happen for about 3-5 days, then go away for a few weeks, then come back, etc.

As well, when this is happening, my engine runs fine (at 100%) right up until about 4500rpm when it just loses all power, it still runs fine, doesn't misfire, or anything, it is as if the engine just limits power to the engine.

No SES lights either.

Please Help!

(and I searched but couldn't find any answers)

[hockeyman]

Tuneup, seafoam, air filter, etc.
I don't have any other suggestions.

[MikeV6]

I think it might be my fuel injector?

[MikeV6]

Also, what is the little black box that is attached to a bracket behind the alternator. It sits right off the left cylinder bank? It has a small air hose running to the intake, a larger hose running somewhere else and a wire harness. They all plug in on one side, but the box goes nowhere.

[98Camaro3.8]

Originally posted by MikeV6:
Also, what is the little black box that is attached to a bracket behind the alternator. It sits right off the left cylinder bank? It has a small air hose running to the intake, a larger hose running somewhere else and a wire harness. They all plug in on one side, but the box goes nowhere.

That's the EVAP purge solenoid. Controls when the EVAP system purges into the intake manifold.

[MikeV6]

when, my bracket is broken and one of the hoses was lose, could that cause this problem?