FortKnox

I recently bought a 1987 Trans Am. This is my first project car, and I'm encountering problems that are a little beyond my knowledge. So, here are the two problems I hope to address first.

1. When the car is in gear, and I am stopped at a light etc., the car idles around 400rpm. It feels rough and definitely brings out the rattles in the car. Is this a normal idle speed? It doesn't feel right to me. I already put new spark plugs and wires, and they helped, but it still idles low.

2. When I start the car from sitting a while, it starts fine, but if I press the gas (either in park or in gear), it begins to stall. Usually I can save it from stalling by letting go of the gas. I'm trying to figure out what this is, but don't have a clue.

Any answers? Got my dream car, and hope to fix it up with a little help.

Thanks.

camaronewbie

Check for vacuum leaks - any vacuum lines need replacing?

Is it a carbed car, TPI, or TBI? I don't think TBI was made until 1988, but ... what induction?

Vader

Normal curb idle when fully warmed should be about 600-625 in Drive. 400 is far too low. Check the IAC and air passages.

The lean condition at throttle tip-in can be due to low fuel pressure, poor injector spray pattern, improperly adjusted IAC, and vacuum leaks.

Start with the easy items like cleaning the throttle body, IAC, setting the throttle minimum air position, and setting the TPS voltage at closed throttle. There are numerous posts here with explicit instructions for all of that.

FortKnox

To answer camaronewbie, carbed.
Thank you both for the useful information. Will be looking into these solutions as soon as I get the chance.