I have a 1987 Firebird with a 2.8L and the 700R-4. When it is first started it idles so low that it stalls unless you pump the gas to keep it going. Once it warms up the Idle keeps increasing the warmer it gets all the way up to 4000ish, maybe higher but we shut it off around then. The transmission was changed recently and after that it overheated because the fan did not turn on. That's when the idle problem first started. We direct wired the fan to keep the motor cool and I have changed from a parts car with known good parts the fuel injectors, fuel rail, new fuel filter, the throttle body, thermostat, all the sensors on the throttle body, the distributor, the plugs, wires, cap, rotor, coil, cold start sensor, and the MAF. Also I checked all the vaccum lines for leaks and changed the intake manifold gaskets. The problem is still there and can't figure it out. The timing has also been checked a few dozen times and there is an exhaust leak on the headers pretty bad. Would that leak cause it? or Could it be the O2 sensor? Those are about the only two things I haven't done yet. I checked the compression with my finger in the plug holes, would that be enough to tell if the head gasket is blown? Could it be a head gasket?

 

Do you have your engine light on ? If you do see what code you have . I am not sure but it cuold be the idle air control even though you may have changed it .I would need more info to be able to tell you more .

 

check engine light doesn't come on.

 

The idle air control motor (the 4 wire thing on the TB) is either stuck WIDE open or your ECM isn't sending it a signal to extend the pintle. I would check the connections between the ECM and the motor before you do anything else. Either that, or you have a really big vacuum leak somewhere.
As for the fan, you could have either a bad switch (pass side head near the lifting eye, squeeze the connector to remove it), a bad relay, or a bad wire between.
Easiest way to check the head gaskets is to look at the exhaust. White smoke means you have either a cracked block, cracked head, or bad gasket. Or, if the gaskets are broken somewhere else, check for milky oil, which is contaminated with coolant. Other than that, your thumb isn't going to give you cylinder pressure readings, which is what a compression gauge is for.

 

we checked all that and it was fine. i'm able to get a 350 so i'm just going to swap the engine. thanks for the help.

 

What are you going to do with the 2.8? If you're going to part it, I call dibs on the fuel injectors.

 

he can have the injectors..... i want the rest of the motor

 

^ little does this guy realize that 88+ got smaller injectors...

 

a buddy of mine is actually taking it off my hands.

 

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mav i already have bigger injectors ...i was wanting the plen was going to try to fab something up like a high rise intake but don't want to mess mine up need a spare pair