I have a 99 ext cab Z71 with the 5.3 liter. My gas guage is working or not irractically. The ABS and Parking Brake lights are staying on for a while then going off. The check engine light just recently came on as well. It has not gone off yet..This is my first GMC and I looking for some advice.

For the check light get a code reader, plug it in and read the code. The code reader has a book that will tell you what the code means. Gas gauge, sounds like a bad ground.

Thanks for the info. I'll give it a try.

Try this out for your fuel gauge; with the key on, engine on/off (doesn't really matter) and an eye on the gauge, give the truck a good side-to-side rocking and then watch the gauge. If the needle starts bouncing all over the place and your "low fuel" light turns on and off, it's very likely a fuel level sensor.

The ABS/brake light issue needs to be addressed by someone who has a scanner capable of retrieving ABS codes.

Thanks for the info. I'll give it a try when I get back home..(traveling) My check engine light was a knock sensor probably caused by some crappy gas and my lead foot. It has not come back after having it checked/cleared. The ABS and parking brake light was possibly caused by a bad battery. The battery was five years old and was on the lower cusp of being bad under load. It also had a low surface charge. It also has not come back. I still have the gas guage issue I'll deal with..

I have a 99 ext cab Z71 with the 5.3 liter. My gas guage is working or not irractically. The ABS and Parking Brake lights are staying on for a while then going off. The check engine light just recently came on as well. It has not gone off yet..This is my first GMC and I looking for some advice.

i've had the same problem with my '99 fuel guage, and i've had it checked out. the problem is in the float sensor within the tank. i was told to fix it requires removing the tank, and i said screw that. the guage works most of the time, but i just go by my mileage to know how much gas i have left.