Chevrolet Repair: Check Engine light Car Stalling and Flooding, knock sensor, light car

Question
Hi,
I will be as exact as possible.  I have a 1991 3.1 Multiport Grand Prix 130,000 miles.  It starting idling wild and flooding and stalling. It ran good  this morning then went back to stalling this afternoon. I tuned it up wires, plugs, fuel filter and air filter and  fuel injection cleaner in the tank.   I checked the fuel pressure at the rail it was 38 psi.
I run the codes after someone told me how too with  a paper clip.  The code read 23, 43 and 53. 23 is IATor Mat sensor and 43 is Knock sensor and 53 is overvolt of the ECM.    Can you  give me guiadance what to do to correct the flooding and stalling.  I Thank You in Advance Sincerely Jeffrey D Price

Answer
Hello Jeffery, Couple of things on this one. The ECM (computer)was a common failure on this car and engine. I think this is your problem because it will run ok for a while then not ok. The other thing is the EGR valve. Disconnect it when it runs poorly and see if that helps it.


Hope this helps...

Have a Great Day    Mark