I have a 1998 Pontiac Firebird 3800 car starts soon after dies out. I was getting a code saying to replace my throttle position sensor. Then it said engine cooling sensor. I replace both now car starts as soon as the dogs out what's next

SOURCE: engine stalls

your on the right route but also check egr valve

SOURCE: throttle position sensor

HI
did your car have (ETS) electronic throttle control system
the TPSis a part of this system
but you can test it by using diagnoses scan tool to check the TPS value when press or depress the accelerator pad.
so you can tell us the NO. of DTC for example(P0122)
ASK FOR MORE INFORMATION

Marvin

• 85242 Answers
• Posted on Aug 28, 2008

SOURCE: 1995 pontiac bonneville 3800 v6

P0321 Spark Reference Circuit. The spark reference signal is used by the PCM to improve ignition timing accuracy during crank and at engine speeds of up to 1,200 RPM. The spark reference circuit allows the use of ignition control mode below 400 RPM, eliminating the need to utilize module mode during start-up, and also allows the PCM to calculate true crankshaft position in 1/6 the time that use of the fuel control reference signal would permit. During normal operation, the PCM uses the spark reference signal to control ignition timing until the engine speed exceeds 1200 RPM, at which time the fuel control reference signal is used. There is no connection to the TCS.
If everything checks ok then the PCM is defective PCM.

SOURCE: Missing, stalling Pontiac Sunfire

The OBD II code for P0400 is Exhaust Gas Recirculation Flow Malfunction.
I'm sure the only thing you have left is you may have to replace the EGR valve or check for any leak from the vaccum lines going to to EGR valve.