I just got my car scanned today, and i got three codes,

-Po101: Airflow out of range
-Po300: Random Misfire
-Po400: EGR system flow malfunction

Any ideas on what these could be? the airflow out of range code, i'm thinking, might have been caused when my air filter fell off, which was off for about a week until i realized, and put it back on. The other two i am unsure about. Also, would any one of these three cause the SES light to go on? Rather, would the airflow code by itself set the light off, or the random misifire? It has been on for several months now, but the car drives very well, with no problems. Thanks for the suggestions.

 

Multiple codes at the same time are indicative of an alternator that is bad. Putting out too much AC and driving the PCM nuts. One way to check very easily is to use a DVM and check between the negative terminal of the battery and the output terminal of the alternator. Set the meter to AC. You do not want to see anymore than 0.03V AC. If it is higher, then chances are the PCM is getting wacked out by the AC input.

A suggestion, maybe the big thumping amp(BTA) you have is killing the alternator since you have what (1000 watts) if I understand your signature.

Let's do a little math. Remember Power(watts "W") = voltage("V") * current("I"). So let's figure the current comsumption of the little heater your running your speakers with. 1000 W = 12 V * I (current) and let's calculate the current you're likely to draw at peak useage.

I (current) = 1000W/ 12V therefore 1000/12 = 83amps. Now if you assume the alternator you have according to your home page, is correct, is a 140AMP job. On a nice hot summer evening with the AC cranking and the lights on and your BTA going. I can just smell the alternator from here in VA.

But who am I to complain when someone pulls up next to me with bass so high the local college can read it on their seismograph.

 

I have been reading the other posts regarding the egr code, and now that i think of it i do get the surging of power off idle to about 2200 rpm, indicating that the egr valve may be faulty.