Hello guys and gals, I have an 07 mustang GT that has been having multiple issues. The main issue is #1-4 ( passenger side) spark plugs are getting destroyed, I’ve used stock, E2, and most recently brisk 450hp race plugs and all the tips end up missing and the motor runs like $hit. So far I’ve replaced injectors, coil packs and plugs. What could be causing this. Issue#2-coolant disappears after a couple days. No leaks, oil looks good and combustion chamber test thru the radiator with the blue dye was good, so shouldn’t be the head gaskets, I’m thinking the hose under the manifold on top of block is leaking. #3 - P0171/P0174 banks 1&2 lean-smoke machine tested found small leak from bottom rear passenger side of intake manifold, possibly need to change the o-ring style gaskets. The car is 07 manual, shorty headers, JLT intake and tune. Any help is appreciated

 

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These are the first 3 plugs pulled, but all 4 on passenger look the same