Questions and Answers

Pontiac Firebird Engine And Heater Q. I have a 1990 Pontiac Firebird. V-6 3.9 liter, automatic transmission, 168,000, fuel injection, A/C, power steering and cruise control. I have a problem with the car wanting to stay running. I have put an ignition module in, distributor, rotor, plugs, plug wires, had it timed. It will run at the 1,000 rpm then when I apply the brakes it will try to go to 500 and try to die.

It is acting as if it is getting too much air. This problem has been going on for awhile but never this bad. I just can't figure this one out. In March I replaced the water pump, thermostat and heater core. The car ran hot but would no heat would come out of the heater. You can even touch the hoses coming from the firewall and they are just a cool as everything. I have changed the antifreeze and everything.

These are the two problems that I have had with my car that I cannot find anything written about this particular problem. Please help. All I can get out of repair shops is for me to put it on a computer for $80.00.

Thanks so much,
Peggy

A. Engine. You need to get some basic idea of engine health. A fuel pressure test, a vacuum gauge to see what the reading is. You need these readings to rule out fuel problems and vacuum leaks. Sometimes you can lightly spray carburetor cleaner around the intake gasket area to see if the rpm's pick up. If so, this would lead me to believe there is a vacuum leak. Also make sure the EGR valve isn't stuck partially open.

Heater. There should be a heater control valve in one of the hoses that goes to the engine. This valve is operated by vacuum. It's supposed to keep hot water from flowing through the heater core if the A/C is on. It may be stuck shut and not allowing water to flow, thus, no heat.