It may have to go to a mechanic. It sounds like this is getting above my head and certainly beyond the time I have to tinker with it. [quote=Hotrod Lincoln]Do a power balance test and a cylinder leakdown test. You need to pinpoint the cause of the compression loss on cylinder #5. No amount of tuning or tinkering is going to compensate for a leaky or tight valve. Always do a valve adjustment BEFORE doing a compression test! Jerry [/quote]