jshaw

Thanks.

I've replaced the intake manifold gaskets and done leak downs on either side of cylinder 5 and cylinder 4. I will do the rest of them this weekend.

I also found some places where they had similar problems and it was a tuliped valve. Hopefully I can pull off the rockers, put a straight edge across the top of the valves, and see that one of them on cylinder 5 sits up higher than the rest. If that is the case, I'll know that is the problem and will happily rip the heads off.

If I do pull the heads, I have to keep from catching Shipwright's Disease and putting a new cam, headers, etc.

FiredUpZ28

Seems like you checked a lot so just throwin it out there, could be a lifter collapsing under load? Maybe check the crank sensor for debris? It is the misfire monitor after all....

jshaw

Found the problem. The roller on one of the cylinder 5 lifters is galled.

I just wanted to post to help out anyone else who might be having similar issues.

I guess it is time for a new cam now. Any suggestions on what kind to gain HP? I really don't want to add headers and all that stuff.

FiredUpZ28

Glad you found it.

I can't see gaining any power from aftermarket lifters... I can, however, see stock lifters failing at higher load/rpm.... I'd ask around, as I haven't replaced the lifters in mine yet.