Engine bogged down to barly able to run. With squeeling noise. Removed serpintine belt, did not stop problem. Replaced cam sycronizer, stopped some of the noise. But did not fix problem. It does not feel like a timing problem it feels more like a valve problem because of the way the engine is bogging down. Can a compresion test reveal this type of valve failure? Can a timing problem cause this type of bogged down problem?