Recently I had an ITR IM and some other goods put on my 99 Si and it was running great. I started the car and noticed it was rough but let it warm up anyways. So I drove down the street and noticed the CEL light started to blink like 8 times then didn't stay on. Then after that it started blinking again like 6 times and then it stayed on. The car is running rough and has little power so what does the codes for the CEL mean? Any help would be great!

 

Here's what you need to do:

1. Post all of the "other goods" you referred to in your first post. I need to know exactly what you have done to your car.
2. You need to read this to learn how to pull the correct error code.

Once you have done these things you can post the right error code that your engine is throwing and we can find out what is pissing your car off.

 

All the things recently done engine-wise would be 60K service w/ valve adj.,ITR IM,AEM fuel rail,AEM fuel pressure reg.,Fluidyne radiator,and FAL fan all done at the same time by a qualified mechanic/shop. Stuff on there already would be Injen CAI,DC 4-1 header, RSR exhuast, and NGK plugs and wires. I drove it around(at least 150 mlies total) after I got all the stuff done and it ran awesome now it runs rough with no power

 

The CEL flashing while driving indicates a catalyst damaging misfire is in progress.

 

Can't you just jump the wire to check to see what code your pulling ? Anyways if its miss-firing then check your spark plug wire, spark plugs and cap and rotor.