87 c10 305 TBI. Oil pressure gauge is not working. Its all the way to the right? Any way to check oil pressure without it? What are the likely causes for the guage not to work? Will I likely need to remove dash to fix it? I went to Autozone to see if I could pull the codes on the Check Engine light but they said their device only works on 1990 and higher. Whats an economical way to get the codes out? Thanks.