Cadillac Misses at idle ,P0300 ,Northstar , With NO Coolant loss

If you have had to add coolant , then check for head gasket leak first . Cadillac Misses at idle ,P0300 ,Northstar This Cadillac DTS has a misfire only at idle . I hooked the scanner up and saw a p0300 code . The fuel trims seemed just a little high at idle but not over 10 . I looked at misfire counts to see which cylinders on this Cadillac DTS ,Northstar was missing . #1 cylinder on this Northstar engine was showing the misfires Any thing above idle the Cadillac ran fine so i started looking for a vacuum leak. What i found was the end of the pvc hose that hooks to intake was leaking.We also replaced the intake boot and intake gaskets . The boot is known to go bad so we just went ahead and changed it. If you find one bad vacuum hose be sure to check all the rest for they are probably just as old .
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