start; stall. replaced everything. it's baffling.

[jessinator]

I own a 1998 GP GT with 184,000 miles. Original tranny (surprisingly). I replaced the intake manifold in May. New oil pan and every attachment in August (alomg with new engine and tranny mounts). This engine is properly maintained. Oil changes, tranny maintenance, you name it, I do. My dad runs a NAPA. Recently, I turned the key and just before it stalled, it revved to 7500 RPM and then continued revving from 1000-2700 RPM continually. I drove it home. It was fine in drive position. My first thought was a vacuum leak. Found it--fixed it. Same problem. Then it required a foot on the gas to keep it running. We've replaced the fuel pump, O2 sensor, mass air flow sensor, air filter and soaked the EGR valve in carb clean. After the filter replacement and EGR soak, it started four times in a row and drove fine for three miles. Parked it and now it starts but immediately stalls. What the hell is going on?

 

[matt5112]

7500 rpm is impossible.

My car was epicly stupid like that.

Was balancer, minor exhaust leak and or the tune (you shouldnt have to worry about the last bit there)

does the tach ever drop to zero while the engine is running?

does the Traction light come on when you're not losing traction at all?

 

[jessinator]

It's never dropped to zero until it stalls right after start. It stalls as soon as I bring my key back from start to run position. I know for sure that the exhaust is secure. I've never experienced a problem with the traction control light. I'll check the balancer. Thank you!

 

[BillBoost37]

What codes has it thrown?

 

[jessinator]

O2 sensor just like a Grand Prix always does. My car throws this code everytime it's scanned