Check engine light

On my 98 Tahoe I have the 350 with true dual flowmasters and no cats with a x pipe. Well the check engine light came on and I have the 02sims installed that fool the computer into thinking that 02 Sensors and cats are there. Well there all connected and the flashing red lights are working so I would assume they should be fine. But what would cause the light to come on and read problems with 02sensors? Just trying to fiqure if my 02sims are bad or what.

Did that they said 3 codes all of them dealing with 02.

how many 02s do you have my truck has four. how ever many 02s you have, you have to get the same amout of 02 sims

Try unhooking your battery for half hour or so, this will reset your computer. I had a huge problem with 05 silverado I tryed sims for both Caspers Electronics and www.O2SensorSimulator.com. Both didn't work so I went to my local chev dealer and asked for some on who could go into the computer and eliminate 02 sensor from the computer. They did this and also changed the settings of the computer to give about 25hp. Cost me $150.00 canadian much better then a Hypertech tuner.

you need to keep the pre cat sensors in but you can replace the rear ones with sims, if you replace the front ones with sims you will get problems

I relplaced the ones that are in the rear right after the cats. The front ones are fine I guess. I didnt even see front end ones...I wonder if I can get to the chevy dealer and ahve them do something to the computer to turn those off and have it re powerd like someone mentioned above.