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power loss


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Guys, I have 75,000 miles on the 98 Bird. Last summer I replaced the R/R and stator. A short time after that I noticed a decrease in power above 6,000 rpm. She pulls fine below that. It's just missing that rush of power above 6k she used to have. There's no misfire or anything. Maybe when the stator let go it damaged the coils? I'm thinking it's not a compression issue since she pulls clean up to 6k. Perhaps I need a valve adjustment? Maybe a fuel flow issue, I'm sure there's no fuel filter or fuel pump like on the FI Birds, but there is a tube that runs from the block to the carbs that I think provides vacumm-maybe replace that if it's old/cracked? Maybe a carb sync? I replaced the plugs last summer too. I don't think it's the clutch since the rpm doesn't wander or slip under acceleration.

Any guidance or tips much appreciated.

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Sounds like it could be a fuel issue. The carbed 'birds have a mesh filter in the tank above the fuel tap, it may be partially blocked by contamination & limiting your fuel flow. Maybe you got a bad batch of fuel at some point?

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Never overlook the simple stuff....

All your tubing, if original, is at least ten years old and has been subjected to countless heat cycles. Rubber deteriorates with time, and heat exacerbates the decline. Weak vacuum tubing can actually collapse under high vacuum pressure, choking off performance in the upper rpm ranges - and this is a real bitch to troubleshoot. I'd simply replace all vacuum/vent lines (one at a time, if you want to find the culprit... or culprits) and test as you go. That also gives you the opportunity to double check that all such lines are correctly connected...

I wouldn't be surprised if a vent line were miss-connected... it's a fairly common goof...

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