I recently cracked the y-pipe on my 94 F150 4x4 with the I6. One of the motor mounts was broken and that's what the exhaust guy said caused the pipe to break. I replaced the motor mounts (they definitely needed to be replaced). I had the pipe fixed but now I have another leak. The guy who fixed the pipe didn't want to mess with troubleshooting the remaining leak - he pretty much just installs mufflers and pipes. He suspected a problem with the exhaust manifold gasket. I also talked to a guy at Checker about it and he said the same thing.

My problem is that I got a Chilton's manual for these trucks and looked up how to replace the gasket and it doesn't mention an exhaust manifold gasket (at least not that I could see). It talks about a gasket on the intake manifold but not the exhaust manifold.

Is there an exhaust manifold gasket on this engine?

Also any suggestions on how to troubleshoot this would be appreciated. It sounds fine when idling and under slow acceleration but starts to make some noise when I hit a high rpm just before shifting.

 

There is not a gasket that came from the factory. The ones you get from the parts store are aftermarket. Ford just bolted them right to the block. You can add one if you think the manifold is warped. Check to see if you have a cracked manifold. There is usually discoloration around an exhaust leak on the manifold.