Since last July, I have pumped nearly $3000 into my 97 Camry LE, 4 cyl. Just recently I had the entire exhaust system from the manifold back done. I replaced the battery a couple weeks ago and thought all was fine. Today, while driving, I noticed that the speedometer wasn't working! At that point, I wasn't losing RPMs or anything, but just a few minutes later, not only was the speedometer not working, I was running at 3000RPMs and not going very fast at all! Anyone know what might be causing this? I know that the coil packs are going bad or already bad and am wondering if that might be the cause.