I bought a 92 camaro rs 305 tbi a couple of weeks ago and i find that whenever i start my car the car idles at around 1200 RPM. After ive driven it around for 10-15 min, the car starts idleing at normal speeds, around 520 RPM. Could it be possible that there's a vacuum leak somewhere??

 

The car is supposed to idle high on first start up - all cars should. It's the choke function - engines don't like cold - the choke function of the old days restricted the air flow via the butterflies in the carb, thus increasing the fuel ratio to air, making the engine run rich (and at higher rpm). In newer cars, more fuel is added via the computer and injectors, causing the same effect. A cold engine will not maintain an idle on the same air/fuel ratio as a warm engine - there must be a rich condition for the engine to keep running until it gets warm - thus why everyone waits until "normal operating temp" before diagnosing and tuning an engine.

The colder it is, the longer it will take to warm, and the longer it will run at higher rpm's.

You're not really supposed to drive until the car warms up a bit. In the older days of a mechaical choking function, if you tried to drive, the car would die (not maintain an idle), because the choke functions by "locking" the carb linkage in place until, after a sufficient warm up period, the driver "taps" the gas and releases the locked linkage Since the newer cars computers compensate instead of a mechanical choke function, and there is no "locking" of any linkage, most people don't remember this rule of yesterday, and just jump in and ride. But it's always better for an engine to warm up a bit first, anywhere from 2 to 10 minutes depending on how cold the temps are.

 

hey thanks alot, i just wasn't sure if TBI systems had a choke or not, but now i do