the other day in my 98 blazer my oil pressure gauge went to zero and the cel came on. I got a code p0300 and p0101. The oil pressure gauge started working again but then my fuel gauge dropped to empty and my battery light came on. I shut the car off, waited a minute then fired her back up and everything is working fine. Also I noticed that sometimes when I floor it the lights get dim and it gets real sluggish and runs rough, but only when I floor it. After a short while it clears up. Please tell me where to begin. thanks

 

The first place I would look is the battery terminals...clean and tighten. It could also be a loose or broken ground wire. I had a similar issue once and it turned out to be a loose battery ground cable.

 

I'll check the battery and all grounds. I'll let you know what I find.