Well I thought I had an exhaust leak on my 94 so I was about to get pissed off because they can alot of the time be hard to pin point. I thought about how to go about this when it came to me. I use Seafoam regularly to clean out my engine, but it makes it smoke really bad for a few mins. DING.... 1/3 can of Seafoam and five minutes later......... I have a leak at ALL junction points on my exhaust, starting from the manifold to Y-pipe and even my muffler has a leak in the side. Point being, if you need to find an exhaust leak... Try using Seafoam, just follow the directions on the can (the main vacuum line being the brake booster line) cut the truck off for five mins, start it back up and follow from your manifolds back to the muffler looking for smoke escaping the pipes! Hope this helps someone!!! ((((((Be careful of the exhaust fumes, DO NOT do this except in a WELL ventilated area, the fumes can be extreme))))))

 

You can also get a towel and plug the exhaust pipe and listen to see if it comes out anywhere. My dad taught me that one.