I went to the drags on Wednesday night and made 3 passes, drove home, everything seemed ok. On Thursday, I was driving around, and noticed that my idle was really rough. It was really lurching feeling as I would be braking and nearly stopped, or when I would let off the gas to start accelerating. When I'm just stopped idling, it just feels rough, like I have a miss or something, but when I'm driving it doesn't feel like there's any bogging, surging, or missing. So I was driving around today, and the SES light popped on. I was kinda relieved becuase then I knew I could pull the codes and possibly remedy the problem. It didn't come back on on my way home, but I checked anyway, and it registered a code 45 for rich exhaust being indicated in the O2 sensor circuit, which means that in closed loop, the ECM saw a voltage above .7V for more than 50 seconds, at a throttle angle greater than 2%. Basically the list of possibilities are high fuel pressure, rich injector, leaky injector, HEI sheilding causing interference, the canister purge, MAP sensor reading low, vacuum leak to FPR diaphragm, bad TPS signal, or EGR stuck open. I was leaning toward the MAP sensor readings being off, or the vacuum leak in the FPR diaphragm due to the rough idle.

If anybody has any more input, I'd really appreciate it.

 

Run a fuel pressure gauge on your rail and see if you have to much pressure (Possibly due to a torn diaphram in the FPR).

Thats the first step I'd say

 

Good research previous to posting btw



(another possibility is you got the car really hot dragging and melted/shorted against something?)