I don't have specific enough experience to tell you much more. If you don't have a mechanic that can test it for you, and then you could decide whether to do the job yourself - you will need to investigate more about testing it yourself and maybe find a link to some photos showing some repairs. Try posting this on the forums at www.usmb.net
- those guys will have some suggestions to help pin down the problem (I hope) and maybe some links to photos of how to proceed.
1 Lucky Texan