before i sold my last car, i had the following problem: both rpm and speedo guages either come on when i put the key in and start the car or they dont. It was really pissing me off, I tried wiggling the key and nothing seem to help. In the end I went to a shop and they said it's a bad instrument cluster and a replacement would fix it. Guess what, $400 for a new one, but the shop owner got me one used for $175 and $75 for labor, so everything came out to $250 and solved the problem completely, so I was able to finally put the car up for sale. Hope this helps.